diff --git a/docs/notebooks/BigInts.ipynb b/docs/notebooks/BigInts.ipynb
index 7633eb9..c353e3a 100644
--- a/docs/notebooks/BigInts.ipynb
+++ b/docs/notebooks/BigInts.ipynb
@@ -2,16 +2,14 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 51,
+   "execution_count": 1,
    "id": "73967878",
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
-     "text": [
-      "[0 3 1]"
-     ]
+     "text": []
     }
    ],
    "source": [
@@ -21,16 +19,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 52,
+   "execution_count": 2,
    "id": "b34d58ef",
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
-     "text": [
-      "[0 3 1]"
-     ]
+     "text": []
     }
    ],
    "source": [
@@ -49,36 +45,16 @@
     "This lets us use (Oberon RISC) 32-bit signed ints to store our digits."
    ]
   },
-  {
-   "cell_type": "markdown",
-   "id": "3f77ce91",
-   "metadata": {},
-   "source": [
-    "## Take Two\n",
-    "\n",
-    "This really got away from me the first time.  I think the big mistake ai made was including the middle branch in the recursive branch.\n"
-   ]
-  },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "id": "b2845a8d",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 53,
+   "execution_count": 3,
    "id": "35476eac",
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
-     "text": [
-      "[0 3 1]"
-     ]
+     "text": []
     }
    ],
    "source": [
@@ -87,7 +63,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 54,
+   "execution_count": 4,
    "id": "02a48806",
    "metadata": {},
    "outputs": [
@@ -106,7 +82,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 55,
+   "execution_count": 5,
    "id": "1d276daf",
    "metadata": {},
    "outputs": [
@@ -126,7 +102,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 56,
+   "execution_count": 6,
    "id": "2454e662",
    "metadata": {},
    "outputs": [
@@ -155,7 +131,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 57,
+   "execution_count": 7,
    "id": "8a60b54b",
    "metadata": {},
    "outputs": [
@@ -195,7 +171,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 58,
+   "execution_count": 8,
    "id": "3fc98ccd",
    "metadata": {},
    "outputs": [
@@ -215,7 +191,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 59,
+   "execution_count": 9,
    "id": "b838c4cb",
    "metadata": {},
    "outputs": [
@@ -241,7 +217,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 60,
+   "execution_count": 10,
    "id": "faaac9d6",
    "metadata": {},
    "outputs": [
@@ -262,7 +238,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 61,
+   "execution_count": 11,
    "id": "2a613f36",
    "metadata": {},
    "outputs": [
@@ -284,7 +260,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 62,
+   "execution_count": 12,
    "id": "e97b149d",
    "metadata": {},
    "outputs": [
@@ -305,7 +281,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 63,
+   "execution_count": 13,
    "id": "de4fe588",
    "metadata": {},
    "outputs": [
@@ -323,7 +299,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 64,
+   "execution_count": 14,
    "id": "67bb934b",
    "metadata": {},
    "outputs": [
@@ -343,8 +319,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 65,
-   "id": "3d7ef5a7",
+   "execution_count": 15,
+   "id": "227271a9",
    "metadata": {},
    "outputs": [
     {
@@ -361,7 +337,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 66,
+   "execution_count": 16,
    "id": "b6f77ac6",
    "metadata": {},
    "outputs": [
@@ -389,7 +365,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 67,
+   "execution_count": 17,
    "id": "246c2a58",
    "metadata": {},
    "outputs": [
@@ -409,7 +385,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 68,
+   "execution_count": 18,
    "id": "5a72ce30",
    "metadata": {},
    "outputs": [
@@ -427,7 +403,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 69,
+   "execution_count": 19,
    "id": "59514dcd",
    "metadata": {},
    "outputs": [
@@ -447,7 +423,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 70,
+   "execution_count": 20,
    "id": "f3c19364",
    "metadata": {},
    "outputs": [
@@ -467,8 +443,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 71,
-   "id": "00daba0b",
+   "execution_count": 21,
+   "id": "998512c6",
    "metadata": {},
    "outputs": [
     {
@@ -483,7 +459,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8157b5e7",
+   "id": "0a592c8e",
    "metadata": {},
    "source": [
     "## Addition of Like Signs `add-digits`\n",
@@ -498,7 +474,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "fc9b97e4",
+   "id": "7b0df08e",
    "metadata": {},
    "source": [
     "### The predicate\n",
@@ -517,8 +493,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 72,
-   "id": "77eea97f",
+   "execution_count": 22,
+   "id": "b2d4f3b2",
    "metadata": {},
    "outputs": [
     {
@@ -543,8 +519,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 73,
-   "id": "b3d917b2",
+   "execution_count": 23,
+   "id": "d87fa971",
    "metadata": {},
    "outputs": [
     {
@@ -569,7 +545,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c37e6dc8",
+   "id": "6ce10b89",
    "metadata": {},
    "source": [
     "    P == [bool] ii & not"
@@ -577,7 +553,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2f69bbd1",
+   "id": "3fc5095b",
    "metadata": {},
    "source": [
     "### The base cases\n",
@@ -592,8 +568,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 74,
-   "id": "4a36d545",
+   "execution_count": 24,
+   "id": "491c0846",
    "metadata": {},
    "outputs": [
     {
@@ -617,7 +593,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "518f5c0d",
+   "id": "9f2bdc8d",
    "metadata": {},
    "source": [
     "    P' ≡ [bool] ii |\n",
@@ -627,7 +603,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "87db88e8",
+   "id": "fa51fd49",
    "metadata": {},
    "source": [
     "#### One list empty\n",
@@ -643,8 +619,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 75,
-   "id": "3af0bfc7",
+   "execution_count": 25,
+   "id": "bd51792f",
    "metadata": {},
    "outputs": [
     {
@@ -660,8 +636,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 76,
-   "id": "85030079",
+   "execution_count": 26,
+   "id": "fbf134e2",
    "metadata": {},
    "outputs": [
     {
@@ -678,8 +654,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 77,
-   "id": "e4aafcaa",
+   "execution_count": 27,
+   "id": "90db3359",
    "metadata": {},
    "outputs": [
     {
@@ -697,7 +673,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "76a60ef3",
+   "id": "3b624991",
    "metadata": {},
    "source": [
     "    THEN' ≡ ditch-empty-list THEN''\n",
@@ -711,7 +687,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b84cccef",
+   "id": "c4d9e00f",
    "metadata": {},
    "source": [
     "#### But first  `add-with-carry`\n",
@@ -726,8 +702,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 78,
-   "id": "3333e900",
+   "execution_count": 28,
+   "id": "e86b7b90",
    "metadata": {},
    "outputs": [
     {
@@ -749,8 +725,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 79,
-   "id": "22a7c867",
+   "execution_count": 29,
+   "id": "cd70e18e",
    "metadata": {},
    "outputs": [
     {
@@ -769,8 +745,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 80,
-   "id": "75713ea2",
+   "execution_count": 30,
+   "id": "a27ff9f0",
    "metadata": {},
    "outputs": [
     {
@@ -789,7 +765,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a9417aac",
+   "id": "89b971c9",
    "metadata": {},
    "source": [
     "So the first part of `F` is `[bool_to_int] dipd + +` to get the total, then we need to"
@@ -797,8 +773,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 81,
-   "id": "b4f1000f",
+   "execution_count": 31,
+   "id": "74a59ab5",
    "metadata": {},
    "outputs": [
     {
@@ -817,8 +793,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 82,
-   "id": "ffbdf325",
+   "execution_count": 32,
+   "id": "3a8f5078",
    "metadata": {},
    "outputs": [
     {
@@ -839,7 +815,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f09689c3",
+   "id": "2b7eb5d7",
    "metadata": {},
    "source": [
     "Put it all together and we have:\n",
@@ -852,8 +828,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 83,
-   "id": "b8161efb",
+   "execution_count": 33,
+   "id": "c05bcd8e",
    "metadata": {},
    "outputs": [
     {
@@ -871,8 +847,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 84,
-   "id": "0f082af7",
+   "execution_count": 34,
+   "id": "03649114",
    "metadata": {},
    "outputs": [
     {
@@ -891,8 +867,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 85,
-   "id": "a0d656bf",
+   "execution_count": 35,
+   "id": "9dca0fbc",
    "metadata": {},
    "outputs": [
     {
@@ -911,8 +887,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 86,
-   "id": "fb7065be",
+   "execution_count": 36,
+   "id": "c8f01d7d",
    "metadata": {},
    "outputs": [
     {
@@ -931,8 +907,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 87,
-   "id": "9b91363f",
+   "execution_count": 37,
+   "id": "a1e77990",
    "metadata": {},
    "outputs": [
     {
@@ -951,8 +927,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 89,
-   "id": "5596f574",
+   "execution_count": 38,
+   "id": "b46a62ba",
    "metadata": {},
    "outputs": [
     {
@@ -967,7 +943,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "861e6896",
+   "id": "44429ac5",
    "metadata": {},
    "source": [
     "### Now back to `add-carry-to-digits`\n",
@@ -990,7 +966,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "26ba75fb",
+   "id": "6895e78b",
    "metadata": {},
    "source": [
     "That leaves the recursive branch:\n",
@@ -1004,7 +980,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4d66332b",
+   "id": "b2279fc8",
    "metadata": {},
    "source": [
     "We know that the Boolean value is `true`.  We also know that the list will be non-empty, but only on the first iteration of the `genrec`.  It may be that the list is empty on a later iteration.\n",
@@ -1016,7 +992,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4ed0fd33",
+   "id": "379d88db",
    "metadata": {},
    "source": [
     "If it's empty...\n",
@@ -1030,7 +1006,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e82f8749",
+   "id": "9f1e5b30",
    "metadata": {},
    "source": [
     "If it's not empty...\n",
@@ -1044,7 +1020,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "07f1bc97",
+   "id": "d5898c6a",
    "metadata": {},
    "source": [
     "Ah ha!?  How to get that `(a+1)` back into the list!?\n",
@@ -1066,7 +1042,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9bfc7127",
+   "id": "13513fab",
    "metadata": {},
    "source": [
     "There we go.\n",
@@ -1080,8 +1056,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 90,
-   "id": "6bd105a9",
+   "execution_count": 39,
+   "id": "c8f1aa44",
    "metadata": {},
    "outputs": [
     {
@@ -1102,8 +1078,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 91,
-   "id": "39244b26",
+   "execution_count": 40,
+   "id": "1fa115d9",
    "metadata": {},
    "outputs": [
     {
@@ -1122,8 +1098,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 92,
-   "id": "0a921fd7",
+   "execution_count": 41,
+   "id": "79d9c526",
    "metadata": {},
    "outputs": [
     {
@@ -1142,8 +1118,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 93,
-   "id": "94359309",
+   "execution_count": 42,
+   "id": "bb030214",
    "metadata": {},
    "outputs": [
     {
@@ -1162,8 +1138,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 94,
-   "id": "d5d4de95",
+   "execution_count": 43,
+   "id": "5e0a05af",
    "metadata": {},
    "outputs": [
     {
@@ -1182,8 +1158,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 95,
-   "id": "a34b4771",
+   "execution_count": 44,
+   "id": "7c730d6d",
    "metadata": {},
    "outputs": [
     {
@@ -1200,7 +1176,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "181cdfd4",
+   "id": "cf558731",
    "metadata": {},
    "source": [
     "So that handles the cases where one of the two lists (but not both) is empty.\n",
@@ -1213,7 +1189,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 96,
+   "execution_count": 45,
    "id": "5e5ddf74",
    "metadata": {},
    "outputs": [
@@ -1233,7 +1209,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 97,
+   "execution_count": 46,
    "id": "c57d1fb2",
    "metadata": {},
    "outputs": [
@@ -1253,7 +1229,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 98,
+   "execution_count": 47,
    "id": "59b1338c",
    "metadata": {},
    "outputs": [
@@ -1269,7 +1245,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c4454f63",
+   "id": "7687e503",
    "metadata": {},
    "source": [
     "The story so far...\n",
@@ -1295,7 +1271,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "54632eea",
+   "id": "fa6dc5c6",
    "metadata": {},
    "source": [
     "### And recur...\n",
@@ -1305,7 +1281,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "995bd8d3",
+   "id": "53b2a650",
    "metadata": {},
    "source": [
     "First we will want to `uncons` the digits"
@@ -1313,8 +1289,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 99,
-   "id": "02c19af8",
+   "execution_count": 48,
+   "id": "78dec757",
    "metadata": {},
    "outputs": [
     {
@@ -1333,7 +1309,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9557420b",
+   "id": "435069f2",
    "metadata": {},
    "source": [
     "#### `uncons-two`\n",
@@ -1342,8 +1318,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 100,
-   "id": "5d671aa4",
+   "execution_count": 49,
+   "id": "5b4bd2fe",
    "metadata": {},
    "outputs": [
     {
@@ -1364,8 +1340,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 102,
-   "id": "80eab7d7",
+   "execution_count": 50,
+   "id": "f284ea19",
    "metadata": {},
    "outputs": [
     {
@@ -1380,7 +1356,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a47c67cf",
+   "id": "2b49246f",
    "metadata": {},
    "source": [
     "    bool a b [...] [...] R0' [add-digits'] R1\n",
@@ -1406,8 +1382,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 103,
-   "id": "a16c95cf",
+   "execution_count": 51,
+   "id": "8adffacb",
    "metadata": {},
    "outputs": [
     {
@@ -1426,13 +1402,13 @@
     "[THEN' ditch-empty-list add-carry-to-digits] inscribe\n",
     "[ELSE pop swap [] [1 swons] branch] inscribe\n",
     "[R0 uncons-two [add-with-carry] dipd] inscribe\n",
-    "[R1 i cons] inscribe\n"
+    "[R1 i cons] inscribe"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 104,
-   "id": "66176a8f",
+   "execution_count": 52,
+   "id": "5b2e5738",
    "metadata": {},
    "outputs": [
     {
@@ -1449,8 +1425,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 105,
-   "id": "e0272194",
+   "execution_count": 53,
+   "id": "cd7ac0b9",
    "metadata": {},
    "outputs": [
     {
@@ -1467,8 +1443,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 106,
-   "id": "bec3b32d",
+   "execution_count": 54,
+   "id": "50f2e62c",
    "metadata": {},
    "outputs": [
     {
@@ -1485,8 +1461,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 107,
-   "id": "6d8b0054",
+   "execution_count": 55,
+   "id": "54ca630f",
    "metadata": {},
    "outputs": [
     {
@@ -1503,8 +1479,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 108,
-   "id": "c842f875",
+   "execution_count": 56,
+   "id": "27bb4638",
    "metadata": {},
    "outputs": [
     {
@@ -1521,8 +1497,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 109,
-   "id": "80a240b0",
+   "execution_count": 57,
+   "id": "4d2d446a",
    "metadata": {},
    "outputs": [
     {
@@ -1539,7 +1515,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "558e0a6d",
+   "id": "0159b2e3",
    "metadata": {},
    "source": [
     "243 + 999 = "
@@ -1547,8 +1523,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 110,
-   "id": "31aa6611",
+   "execution_count": 58,
+   "id": "c187ffff",
    "metadata": {},
    "outputs": [
     {
@@ -1565,1805 +1541,11 @@
   },
   {
    "cell_type": "markdown",
-   "id": "db2de9c5",
+   "id": "c142268c",
    "metadata": {},
    "source": [
     "Bitchin'"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "a46d9942",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "4fe39366",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "ef9db281",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "834ee60c",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "20a2809e",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "b74e8780",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "b2765992",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "c96c51a5",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "markdown",
-   "id": "50665e75",
-   "metadata": {},
-   "source": [
-    "### Predicate\n",
-    "so the predicate for the whole thing would be"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 121,
-   "id": "187aa6ec",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[_add_p [bool not] ii &] inscribe"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 123,
-   "id": "ee3d2316",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "true"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[][]_add_p"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 124,
-   "id": "7e8c4942",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[1][]_add_p"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 125,
-   "id": "8b41766c",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[][1]_add_p"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 126,
-   "id": "1bacc617",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[1][1]_add_p"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "978b5cac",
-   "metadata": {},
-   "source": [
-    "### Recursive Branch\n",
-    "So (ignoring the source of the initial carry bit for now) we have:\n",
-    "\n",
-    "    _add_p == [bool not] ii &\n",
-    "    _add_then == pop swap [] [1 swons] branch\n",
-    "\n",
-    "    add_digits == [_add_p] [_add_then] [R0] [R1] genrec\n",
-    "\n",
-    "What should the recursive branch do?\n",
-    "\n",
-    "It will be some `ifte` expression:\n",
-    "\n",
-    "    R0 [add_digits] R1 == [P] [THEN] [ELSE] ifte\n",
-    "\n",
-    "Ideally, we can arrange to neatly bracket the `[add_digits]` quote, but otherwise we can build up the `ifte` quotes in the usual way with `cons` and `concat`."
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "7246fe3d",
-   "metadata": {},
-   "source": [
-    "#### Is One List Empty?\n",
-    "The context will be a Boolean carry bit and two lists, one of which (but not both!) may be empty.\n",
-    "\n",
-    "    carry [a ...] [b ...] R0 [add_digits] R1\n",
-    "\n",
-    "    carry [] [b ...] R0 [add_digits] R1\n",
-    "\n",
-    "    carry [a ...] [] R0 [add_digits] R1\n",
-    "\n",
-    "So I think the first thing to do is detect and handle the (possibly) empty lists?"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "d54e0860",
-   "metadata": {},
-   "source": [
-    "#### predicate"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 92,
-   "id": "728f7b72",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "true"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[1] [1] [bool] ii &"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 93,
-   "id": "3561502a",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[1] [] [bool] ii &"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 94,
-   "id": "2c395fcc",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[] [1] [bool] ii &"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "13993d1f",
-   "metadata": {},
-   "source": [
-    "So our `ifte` predicate is `[bool] ii &`, what's the rest look like?\n",
-    "\n",
-    "    [[bool] ii &] ... [add_digits] ... ifte\n",
-    "\n",
-    "We will need `add_digits` on the `true` branch to deal with the rest of the lists, but not (I think) on the false branch?\n",
-    "\n",
-    "    [[bool] ii &] [... [add_digits] ...] [ELSE] ifte"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 130,
-   "id": "9caf15b4",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "[_add_rec_pred [bool] ii &] inscribe"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "9445eb3c",
-   "metadata": {},
-   "source": [
-    "Plugging in `add-with-carry` we get:"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 118,
-   "id": "7e745018",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "5 false [2 3] [5 6]"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "false [1 2 3] [4 5 6] uncons-two [add-with-carry] dipd"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "121ff3c0",
-   "metadata": {},
-   "source": [
-    "### Recur\n",
-    "\n",
-    "It is at this point that we would recur:\n",
-    "\n",
-    "    5 false [2 3] [5 6] [add_digits] i ...\n",
-    "      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ \n",
-    "\n",
-    "This part runs and becomes some list (possibly empty) of result digits (the base case consumes the carry flag and one list):\n",
-    "\n",
-    "    5 [7 9]\n",
-    "\n",
-    "So our conclusion must be `cons`:\n",
-    "\n",
-    "    5 [7 9] cons\n",
-    "    [5 7 9]\n",
-    "\n",
-    "And our whole branch function is:\n",
-    "\n",
-    "    THEN == uncons-two [add-with-carry] dipd [add_digits] i cons\n",
-    "\n",
-    "    [_add_rec_pred] [THEN] [ELSE] ifte\n",
-    "\n",
-    "It's a little tricky having that recursive call being nested like that:\n",
-    "\n",
-    "    THEN0.1 == [add-with-carry] dipd\n",
-    "    THEN0 == uncons-two THEN0.1\n",
-    "    THEN1 == i cons\n",
-    "\n",
-    "    [_add_rec_pred] [THEN0 [add_digits] THEN1] [ELSE] ifte\n",
-    "\n",
-    "But we can make it work."
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "cd576704",
-   "metadata": {},
-   "source": [
-    "#### Interlude: Nested or Unnested?\n",
-    "\n",
-    "    F == [P] [THEN] [R0]   [R1] genrec\n",
-    "    F == [P] [THEN] [R0 [F] R1] ifte\n",
-    "\n",
-    "Our recursive branch will take the form of an `ifte` expression that incorporates the function `[F]` into one of its branches:\n",
-    "\n",
-    "    F == [P] [THEN] [[P0] [THEN0   [F]   THEN1]             [ELSE] ifte] ifte\n",
-    "\n",
-    "    F == [P] [THEN] [[P0] [THEN0]] [F] [[THEN1] cons concat [ELSE] ifte] ifte\n",
-    "\n",
-    "\n",
-    "\n",
-    "       [P0] [THEN0] [F] [THEN1] cons concat [ELSE] ifte\n",
-    "    ------------------------------------------------------\n",
-    "       [P0] [THEN0] [[F] THEN1]      concat [ELSE] ifte\n",
-    "    ------------------------------------------------------\n",
-    "       [P0] [THEN0   [F] THEN1]            [ELSE] ifte\n",
-    "    ------------------------------------------------------\n",
-    "       [P0] [THEN0 [F] THEN1] [ELSE] ifte\n",
-    "\n",
-    "It's awkward but it works."
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 112,
-   "id": "4fcf1d97",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "aa76c2fc",
-   "metadata": {},
-   "source": [
-    "#### add-carry-to-digits\n",
-    "So now we have `carry` and one list of digits.  (We also know that we have at least one digit in the list at this point but we likely won't need that information.)\n",
-    "\n",
-    "    carry [a ...] add-carry-to-digits\n",
-    "\n",
-    "I think once we define `add-carry-to-digits` we are pretty much done?  Let's find out."
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "828699dc",
-   "metadata": {},
-   "source": [
-    "##### If `carry` is `false` we just return the digits list, eh?\n",
-    "\n",
-    "       false [a ...] swap [] [THEN] branch\n",
-    "    -----------------------------------------\n",
-    "             [a ...]"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "2a386fe2",
-   "metadata": {},
-   "source": [
-    "##### If `true` we want to maybe reuse `add-with-carry`?\n",
-    "\n",
-    "\n",
-    "       true [a ...] swap [THEN] [] branch\n",
-    "    ----------------------------------------\n",
-    "            [a ...]  THEN\n",
-    "    --------------------------------------\n",
-    "       false 1 a add-with-carry [...] G\n",
-    "    --------------------------------------\n",
-    "       (1+a) carry [...] G\n",
-    "    ------------------------------------------------\n",
-    "       (1+a) carry [...] add-carry-to-digits cons\n",
-    "    ------------------------------------------------\n",
-    "       (1+a)       [...]                     cons\n",
-    "    ------------------------------------------------\n",
-    "             [(1+a) ...]\n",
-    "\n",
-    "So `add-carry-to-digits` is a recursive function (not a `branch` after all.)"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "08a149fa",
-   "metadata": {},
-   "source": [
-    "Omitting `ditch-empty-list` for the moment:\n",
-    "\n",
-    "    THEN == [false 1] dip uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "\n",
-    "    [a ...] THEN\n",
-    "    [a ...] [false 1] dip uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "    false 1 [a ...]       uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "    false 1 a [...]              [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "    false 1 a add-with-carry [...]                    [add-carry-to-digits] i cons\n",
-    "    (1+a) false              [...]                    [add-carry-to-digits] i cons\n",
-    "    (1+a) false              [...]                     add-carry-to-digits    cons\n",
-    "    (1+a)                    [...]                                            cons\n",
-    "    [(1+a) ...]\n",
-    "\n",
-    "QED"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 64,
-   "id": "9f4ebfd9",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "afd8074b",
-   "metadata": {},
-   "source": [
-    "#### add-carry-to-digits, recursively\n",
-    "\n",
-    "    carry [...] add-carry-to-digits\n",
-    "\n",
-    "    carry [...] [P] [THEN] [R0] [R1] genrec\n",
-    "\n",
-    "So:\n",
-    "\n",
-    "    P == swap not\n",
-    "    \n",
-    "-or-\n",
-    "\n",
-    "    P == pop not\n",
-    "    \n",
-    "and\n",
-    "\n",
-    "    THEN == popd\n",
-    "\n",
-    "That leaves:\n",
-    "\n",
-    "    true [...] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "I am tempted to leave the transformation from the above form to\n",
-    "\n",
-    "    true [...] popd [false 1] dip uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "\n",
-    "as the proverbial \"exercise for the reader\" but it's kinda trivial:\n",
-    "\n",
-    "    R0 == popd [false 1] dip uncons [add-with-carry] dip\n",
-    "    R1 == i cons\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 65,
-   "id": "0c095d53",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "2 false [2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "true [1 2 3]  popd [false 1] dip uncons [add-with-carry] dip"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 66,
-   "id": "e793bd13",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "2 [2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "popd"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 67,
-   "id": "e5d3966a",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[2 2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "cons"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 73,
-   "id": "c8aec12d",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "[add-carry-to-digits [pop not] [popd] [popd [false 1] dip uncons [add-with-carry] dip] [i cons] genrec] inscribe"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 74,
-   "id": "d290d896",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[2 2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "true [1 2 3] add-carry-to-digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 75,
-   "id": "10cb7a1f",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[1 2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "false [1 2 3] add-carry-to-digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 84,
-   "id": "89298766",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "true [2147483647 2147483647 2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "true base -- dup [2 3] ccons"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 85,
-   "id": "af73db1b",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[0 0 3 3]"
-     ]
-    }
-   ],
-   "source": [
-    "add-carry-to-digits"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "69f59f45",
-   "metadata": {},
-   "source": [
-    "E.g. 3299 + 1 = 3300"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 90,
-   "id": "00fa293e",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false [2147483647 2147483647 2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "false base -- dup [2 3] ccons"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 91,
-   "id": "227a28f1",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[2147483647 2147483647 2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "add-carry-to-digits"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "50d06f33",
-   "metadata": {},
-   "source": [
-    "So that seems like it works."
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 119,
-   "id": "7e735e04",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "b55599cb",
-   "metadata": {},
-   "source": [
-    "## Our Story So Far...\n",
-    "    _add_p == [bool not] ii &\n",
-    "    _add_then == pop swap [] [1 swons] branch\n",
-    "    _add_rec_pred == [bool] ii &\n",
-    "\n",
-    "    add_digits == [_add_p] [_add_then] [R0] [R1] genrec"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "f515f498",
-   "metadata": {},
-   "source": [
-    "Where:\n",
-    "\n",
-    "                    R0 [add_digits] R1\n",
-    "    -----------------------------------------------------\n",
-    "       [_add_rec_pred] [          THEN          ] [ELSE] ifte\n",
-    "    -----------------------------------------------------\n",
-    "       [_add_rec_pred] [THEN0 [add_digits] THEN1] [ELSE] ifte\n",
-    "\n",
-    "    THEN0 == uncons-two [add-with-carry] dipd\n",
-    "\n",
-    "    THEN1 == i cons\n",
-    "\n",
-    "    ELSE == ditch-empty-list add-carry-to-digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 131,
-   "id": "348e377d",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "[THEN0 uncons-two [add-with-carry] dipd] inscribe\n",
-    "[THEN1 i cons] inscribe\n",
-    "[ELSE ditch-empty-list add-carry-to-digits] inscribe"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "c3b2768f",
-   "metadata": {},
-   "source": [
-    "Recalling:\n",
-    "\n",
-    "       [P0] [THEN0] [F] [THEN1] cons concat [ELSE] ifte\n",
-    "    ------------------------------------------------------\n",
-    "       [P0] [THEN0] [[F] THEN1]      concat [ELSE] ifte\n",
-    "    ------------------------------------------------------\n",
-    "       [P0] [THEN0   [F] THEN1]            [ELSE] ifte\n",
-    "    ------------------------------------------------------\n",
-    "       [P0] [THEN0 [F] THEN1] [ELSE] ifte"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "2d58b809",
-   "metadata": {},
-   "source": [
-    "Ergo:\n",
-    "\n",
-    "    R0 == [_add_rec_pred] [THEN0]\n",
-    "    R1 == [THEN1] cons concat [ELSE] ifte\n",
-    "\n",
-    "    add_digits == [_add_p] [_add_then] [R0] [R1] genrec\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 132,
-   "id": "2219756c",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "[_add_R0 [_add_rec_pred] [THEN0]] inscribe\n",
-    "[_add_R1 [THEN1] cons concat [ELSE] ifte] inscribe"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 133,
-   "id": "80866347",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "[add_digits [_add_p] [_add_then] [_add_R0] [_add_R1] genrec] inscribe"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 134,
-   "id": "51314100",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false [3 2 1] [8]"
-     ]
-    }
-   ],
-   "source": [
-    "false [3 2 1] [8] "
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 135,
-   "id": "63a589cb",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[11 2 1]"
-     ]
-    }
-   ],
-   "source": [
-    "add_digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 136,
-   "id": "b5c5b50b",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[2147483647 11 2 1]"
-     ]
-    }
-   ],
-   "source": [
-    "base -- swons"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 137,
-   "id": "1c81b4bc",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false [2147483647 11 2 1] [23]"
-     ]
-    }
-   ],
-   "source": [
-    "false swap [23]"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 138,
-   "id": "cdd845ef",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[22 12 2 1]"
-     ]
-    }
-   ],
-   "source": [
-    "add_digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 142,
-   "id": "583a2390",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[2147483647] [1]"
-     ]
-    }
-   ],
-   "source": [
-    "clear base -- unit [1]"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "defedd4b",
-   "metadata": {},
-   "source": [
-    "When i tried it it failed and inspection revealed that I had forgotten to set the initial carry value."
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 144,
-   "id": "532967be",
-   "metadata": {
-    "scrolled": true
-   },
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false [2147483647] [1]"
-     ]
-    }
-   ],
-   "source": [
-    "clear false base -- unit [1]"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 145,
-   "id": "e15c8b33",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[0 1]"
-     ]
-    }
-   ],
-   "source": [
-    "add_digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "84c6c958",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 148,
-   "id": "ca5c95af",
-   "metadata": {
-    "scrolled": true
-   },
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "false [2147483647 2147483647 2147483647 2147483647] [1]"
-     ]
-    }
-   ],
-   "source": [
-    "clear false base -- unit dup concat dup concat [1]"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "3a6960ea",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "markdown",
-   "id": "8c32715b",
-   "metadata": {},
-   "source": [
-    "#### I made a mistake in add-carry-to-digits\n",
-    "\n",
-    "The recursive branch:\n",
-    "\n",
-    "    true [...] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "Must also deal with the case where the list is empty!\n",
-    "\n",
-    "    true [] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "The `popd` is okay, but then we need a branch:\n",
-    "\n",
-    "    R0 == popd ? [1 swons] [R0.t] branch\n",
-    "    R0.t == [false 1] dip uncons [add-with-carry] dip\n",
-    "\n",
-    "    R1 == i cons\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "1b4b1302",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "markdown",
-   "id": "cab5271f",
-   "metadata": {},
-   "source": [
-    "#### add-carry-to-digits, recursively, TAKE TWO\n",
-    "\n",
-    "    carry [...] add-carry-to-digits\n",
-    "\n",
-    "    carry [...] [P] [THEN] [R0] [R1] genrec\n",
-    "\n",
-    "    P == pop not\n",
-    "    THEN == popd\n",
-    "\n",
-    "That leaves one of:\n",
-    "\n",
-    "    true [...] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "-or-\n",
-    "\n",
-    "    true [] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "It would be fun to just set `R1` to `ifte`\n",
-    "\n",
-    "    true [] R0 [add-carry-to-digits] ifte\n",
-    "\n",
-    "Which means that `R0` must be a predicate and the \"then\" branch.\n",
-    "\n",
-    "    true [] [bool not] [THEN] [add-carry-to-digits] ifte\n",
-    "\n",
-    "And I think `THEN` would just be:\n",
-    "\n",
-    "    THEN == popd 1 swons\n",
-    "\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 162,
-   "id": "955aed77",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear\n",
-    "[R0.t [false 1] dip uncons [add-with-carry] dip] inscribe\n",
-    "[add-carry-to-digits\n",
-    "  [pop not]\n",
-    "  [popd]\n",
-    "  [[bool not] [popd 1 swons]]\n",
-    "  [ifte]\n",
-    "  genrec\n",
-    "] inscribe"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "1ee5b941",
-   "metadata": {},
-   "source": [
-    "This is still broken because the "
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 160,
-   "id": "8ca1f509",
-   "metadata": {
-    "scrolled": true
-   },
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "true [2147483647 2147483647 2147483647 2147483647]"
-     ]
-    }
-   ],
-   "source": [
-    "clear true base -- unit dup concat dup concat"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "77e2e26f",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "add-carry-to-digits"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "07a528bd",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "97ed01aa",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "dee054a6",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "f92eebb0",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "36e683fd",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "markdown",
-   "id": "91ffeec1",
-   "metadata": {},
-   "source": [
-    "#### add-carry-to-digits\n",
-    "\n",
-    "So `add-carry-to-digits` is a recursive function:\n",
-    "\n",
-    "    carry [a ...] add-carry-to-digits\n",
-    "\n",
-    "    carry [a ...] [P] [THEN] [R0] [R1] genrec\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "dc5f3cba",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "[pop not] [popd] [[bool not] [1 cons swap]] [ifte] genrec"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "6201b301",
-   "metadata": {},
-   "source": [
-    "##### If `carry` is `false` we just return the digits list, eh?\n",
-    "\n",
-    "       false [a ...] [pop not] [popd] [R0] [R1] genrec\n",
-    "    -----------------------------------------------------\n",
-    "             [a ...]"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "2ffbb77c",
-   "metadata": {},
-   "source": [
-    "##### If `true` we want to maybe reuse `add-with-carry`?\n",
-    "\n",
-    "    true [a ...] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "-or-\n",
-    "\n",
-    "    true [] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "Um...\n",
-    "\n",
-    "    true [] [bool not] [1 cons popd] [add-carry-to-digits] ifte\n",
-    "\n",
-    "\n",
-    "    true [] [bool not] [1 cons popd] [add-carry-to-digits] ifte\n",
-    "    true [] 1 cons popd\n",
-    "    true [1] popd\n",
-    "    [1]\n",
-    "\n",
-    "-or-\n",
-    "\n",
-    "    true [a ...] [bool not] [1 cons swap] [F add-carry-to-digits] itfe\n",
-    "    true [a ...] F add-carry-to-digits\n",
-    "\n",
-    "\n",
-    "       true                  [a ...] F add-carry-to-digits\n",
-    "    ---------------------------------------------------------\n",
-    "       true 0 a add-with-carry [...]   add-carry-to-digits\n",
-    "\n",
-    "    \n",
-    "    F == 0 swap uncons [add-with-carry] dip\n",
-    "\n",
-    "\n",
-    "    true [a ...] [bool not] [1 cons swap] [add-carry-to-digits] [F] swoncat itfe\n",
-    "\n",
-    "\n",
-    "\n",
-    "    true [a ...] [bool not] [1 cons swap] [add-carry-to-digits] [0 swap uncons [add-with-carry] dip] swoncat itfe\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 162,
-   "id": "0ee18517",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear\n",
-    "[R0.t [false 1] dip uncons [add-with-carry] dip] inscribe\n",
-    "[add-carry-to-digits\n",
-    "  [pop not]\n",
-    "  [popd]\n",
-    "  [[bool not] [popd 1 swons]]\n",
-    "  [ifte]\n",
-    "  genrec\n",
-    "] inscribe"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "965cf4df",
-   "metadata": {},
-   "source": [
-    "Omitting `ditch-empty-list` for the moment:\n",
-    "\n",
-    "    THEN == [false 1] dip uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "\n",
-    "    [a ...] THEN\n",
-    "    [a ...] [false 1] dip uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "    false 1 [a ...]       uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "    false 1 a [...]              [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "    false 1 a add-with-carry [...]                    [add-carry-to-digits] i cons\n",
-    "    (1+a) false              [...]                    [add-carry-to-digits] i cons\n",
-    "    (1+a) false              [...]                     add-carry-to-digits    cons\n",
-    "    (1+a)                    [...]                                            cons\n",
-    "    [(1+a) ...]\n",
-    "\n",
-    "QED"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 64,
-   "id": "1787863d",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "77eeace6",
-   "metadata": {},
-   "source": [
-    "#### add-carry-to-digits, recursively\n",
-    "\n",
-    "    carry [...] add-carry-to-digits\n",
-    "\n",
-    "    carry [...] [P] [THEN] [R0] [R1] genrec\n",
-    "\n",
-    "So:\n",
-    "\n",
-    "    P == swap not\n",
-    "    \n",
-    "-or-\n",
-    "\n",
-    "    P == pop not\n",
-    "    \n",
-    "and\n",
-    "\n",
-    "    THEN == popd\n",
-    "\n",
-    "That leaves:\n",
-    "\n",
-    "    true [...] R0 [add-carry-to-digits] R1\n",
-    "\n",
-    "I am tempted to leave the transformation from the above form to\n",
-    "\n",
-    "    true [...] popd [false 1] dip uncons [add-with-carry] dip [add-carry-to-digits] i cons\n",
-    "\n",
-    "as the proverbial \"exercise for the reader\" but it's kinda trivial:\n",
-    "\n",
-    "    R0 == popd [false 1] dip uncons [add-with-carry] dip\n",
-    "    R1 == i cons\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "2a37982c",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "0c1ad90d",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "a184d47c",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "0343594a",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "e13c8b2e",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "e921d72a",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "2727bab9",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "3373be97",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "342e9982",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "7f655e89",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "611f40ff",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "bada9caa",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "fb66962d",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "6764903e",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "b4b10bfe",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "[base 2147483648] inscribe\n",
-    "[valid_digit [0 >] [base <] &&] inscribe\n",
-    "[_add_p [bool not] ii &] inscribe\n",
-    "[_add_then pop swap [] [1 swons] branch] inscribe\n",
-    "[_add_rec_pred [bool] ii &] inscribe\n",
-    "[bool_to_int [0] [1] branch] inscribe\n",
-    "[_add-with-carry0 [bool_to_int] dipd + +] inscribe\n",
-    "[_add-with-carry1 base [mod] [>=] clop] inscribe\n",
-    "[add-with-carry _add-with-carry0 _add-with-carry1] inscribe\n",
-    "[uncons-two [uncons] ii swapd] inscribe\n",
-    "[ditch-empty-list [bool] [popd] [pop] ifte] inscribe\n",
-    "[add-carry-to-digits [pop not] [popd] [popd [false 1] dip uncons [add-with-carry] dip] [i cons] genrec] inscribe\n",
-    "[THEN0 uncons-two [add-with-carry] dipd] inscribe\n",
-    "[THEN1 i cons] inscribe\n",
-    "[ELSE ditch-empty-list add-carry-to-digits] inscribe\n",
-    "[_add_R0 [_add_rec_pred] [THEN0]] inscribe\n",
-    "[_add_R1 [THEN1] cons concat [ELSE] ifte] inscribe\n",
-    "[add_digits [_add_p] [_add_then] [_add_R0] [_add_R1] genrec] inscribe\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "11c66f4e",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "60cda31e",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "0852a374",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "c2c3f8f5",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "eb4d2dac",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "6c7f705e",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "8e69a883",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "551b52de",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 55,
-   "id": "3fb6905c",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[1] 2 false [2 3]"
-     ]
-    }
-   ],
-   "source": [
-    "[isnt_bigint\n",
-    "[first isnt_bool]\n",
-    "[rest [isnt_int] map]\n",
-    "cleave cons\n",
-    "] inscribe"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 56,
-   "id": "39b3d4bc",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "[1] 2 false [2 3] [[!] [!-] [!=] [%] [&] [&&] [*] [+] [++] [-] [--] [/] [<] [<<] [<<{}] [<=] [<>] [<{}] [=] [>] [>=] [>>] [?] [abs] [add] [add-with-carry] [all] [anamorphism] [and] [any] [app1] [app2] [app3] [appN] [at] [b] [base] [binary] [bool] [bool_to_int] [branch] [ccccons] [ccons] [choice] [clear] [cleave] [clop] [cmp] [codi] [codireco] [concat] [cond] [cons] [digitalize] [dinfrirst] [dip] [dipd] [dipdd] [disenstacken] [ditch-empty-list] [div] [divmod] [down_to_zero] [drop] [dup] [dupd] [dupdd] [dupdip] [dupdipd] [enstacken] [eq] [first] [first_two] [flatten] [floordiv] [fork] [fourth] [gcd] [gcd2] [ge] [genrec] [getitem] [grabN] [grba] [gt] [help] [i] [ifte] [ii] [infra] [infrst] [inscribe] [isnt_bigint] [isnt_bool] [isnt_int] [isnt_stack] [le] [loop] [lshift] [lt] [make_generator] [manual] [map] [max] [min] [mod] [mul] [ne] [neg] [not] [nulco] [nullary] [of] [or] [over] [pam] [pm] [pop] [popd] [popdd] [popop] [popopd] [popopdd] [popopop] [pow] [pred] [primrec] [product] [quit] [quoted] [range] [range_to_zero] [reco] [remove] [rest] [reverse] [roll<] [roll>] [rolldown] [rollup] [rrest] [rshift] [run] [second] [select] [sharing] [shift] [shunt] [size] [sort] [spiral_next] [split_at] [split_list] [sqr] [stack] [stackd] [step] [step_zero] [stuncons] [stununcons] [sub] [succ] [sum] [swaack] [swap] [swapd] [swoncat] [swons] [tailrec] [take] [ternary] [third] [times] [to_bigint] [trace] [tuck] [unary] [uncons] [unique] [unit] [unquoted] [unswons] [valid_digit] [warranty] [while] [words] [x] [xor] [zip] [|] [||] [•]]"
-     ]
-    }
-   ],
-   "source": [
-    "words"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 57,
-   "id": "4c5edbfa",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": []
-    }
-   ],
-   "source": [
-    "clear"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 58,
-   "id": "1e201000",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "2147483648"
-     ]
-    }
-   ],
-   "source": [
-    "1 31 <<"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "b310e739",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 59,
-   "id": "fc53f72d",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "12 3"
-     ]
-    }
-   ],
-   "source": [
-    "clear\n",
-    "\n",
-    "123 10 divmod"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 60,
-   "id": "2cb7c88f",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "12 0 3"
-     ]
-    }
-   ],
-   "source": [
-    "base divmod"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "e7c36361",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 61,
-   "id": "005ac08e",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "\n",
-      "==== Help on divmod ====\n",
-      "\n",
-      "Similarly to pm (\"Plus or minus\") this function computes\n",
-      "both the\n",
-      "::\n",
-      "\n",
-      "          a b divmod\n",
-      "    ---------------------\n",
-      "       a b div a b mod\n",
-      "    ---------------------\n",
-      "             q r\n",
-      "\n",
-      "Where: q * b + r == a\n",
-      "\n",
-      "---- end ( divmod )\n",
-      "\n",
-      "\n",
-      "12 0 3"
-     ]
-    }
-   ],
-   "source": [
-    "[divmod] help"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "6ebcf6d8",
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {