diff --git a/joy/gui/textwidget.py b/joy/gui/textwidget.py
index 9eea55b..08c1734 100644
--- a/joy/gui/textwidget.py
+++ b/joy/gui/textwidget.py
@@ -49,7 +49,8 @@ import os, sys
 from joy.utils.stack import stack_to_string
 
 from .mousebindings import MouseBindingsMixin
-from .world import World, is_numerical
+from .utils import is_numerical
+from .world import World
 
 
 def make_gui(dictionary):
diff --git a/joy/gui/utils.py b/joy/gui/utils.py
index a83657f..e187d12 100644
--- a/joy/gui/utils.py
+++ b/joy/gui/utils.py
@@ -7,7 +7,15 @@ from dulwich.repo import Repo
 
 
 COMMITTER = 'Joy <auto-commit@example.com>'
-DEFAULT_JOY_HOME = '~/.joypy'
+DEFAULT_JOY_HOME = expanduser(join('~', '.joypy'))
+
+
+def is_numerical(s):
+  try:
+    float(s)
+  except ValueError:
+    return False
+  return True
 
 
 def home_dir(path):
diff --git a/joy/gui/world.py b/joy/gui/world.py
index 4fe4514..14c8dac 100644
--- a/joy/gui/world.py
+++ b/joy/gui/world.py
@@ -28,14 +28,7 @@ from joy.joy import run
 from joy.parser import Symbol
 from joy.utils.stack import stack_to_string
 from joy.utils.types import type_check
-
-
-def is_numerical(s):
-  try:
-    float(s)
-  except ValueError:
-    return False
-  return True
+from .utils import is_numerical
 
 
 class World(object):
@@ -121,7 +114,6 @@ class World(object):
 
 class StackDisplayWorld(World):
 
-  
   def __init__(self, repo, filename, rel_filename, dictionary=None, text_widget=None):
     self.filename = filename
     stack = self.load_stack() or ()
diff --git a/thun/metalogical.pl b/thun/metalogical.pl
index 201fd86..caf4b04 100644
--- a/thun/metalogical.pl
+++ b/thun/metalogical.pl
@@ -10,7 +10,7 @@ tmi(var(A)) :- var(A).
 
 % Meta-logical print trace.
 % (Could also be captured in a list or something instead.)
-tmi(thun(E, Si, _)) :- portray_clause(Si-E), fail.
+tmi(thun(E, Si, _)) :- frump(Si, E), fail.
 
 tmi(Goal) :-
     checky(Goal),
@@ -24,6 +24,33 @@ checky(Goal) :-
     Goal \= number(_),
     Goal \= !.
 
+
+format_state(Stack, Expression, Codes) :-
+    reverse(Stack, RStack),
+    phrase(format_stack(RStack), RStackCodes),
+    phrase(format_stack(Expression), ExpressionCodes),
+    append(RStackCodes, [32, 46, 32|ExpressionCodes], Codes).
+
+
+frump(Stack, Expression) :-
+    format_state(Stack, Expression, Codes),
+    maplist(put_code, Codes), nl.
+
+% do(In) :- phrase(format_stack(In), Codes), maplist(put_code, Codes).
+
+% Print Joy expressions as text.
+
+format_stack(Tail)  --> {var(Tail)}, !, [46, 46, 46].
+format_stack([T])   --> format_term(T), !.
+format_stack([T|S]) --> format_term(T), " ", format_stack(S).
+format_stack([])    --> [].
+
+format_term(N) --> {number(N), number_codes(N, Codes)}, Codes.
+format_term(A) --> {  atom(A),   atom_codes(A, Codes)}, Codes.
+format_term([A|As]) --> "[", format_stack([A|As]), "]".
+
+
+
 /*
 
 [debug]  ?- tmi(thun([1, 2, swap], Si, So)).
diff --git a/thun/thun.pl b/thun/thun.pl
index fe7b7fe..262f3e0 100644
--- a/thun/thun.pl
+++ b/thun/thun.pl
@@ -236,6 +236,13 @@ combo(branch, [T, F,  Expr|S], S, Ei, Eo) :-
 
 combo(loop, [_, false|S], S, E,  E ).
 combo(loop, [B,  true|S], S, Ei, Eo) :- append(B, [B, loop|Ei], Eo).
+combo(loop, [B,  Expr|S], S, Ei, Eo) :-
+    \+ Expr = true, \+ Expr = false,
+    catch(  % Try Expr and do one or the other,
+        (Expr -> append(B, [B, loop|Ei], Eo) ; Ei=Eo),
+        _,  % If Expr don't grok, try both branches.
+        (Ei=Eo ; append(B, [B, loop|Ei], Eo))
+        ).
 
 combo(step, [_,    []|S],    S,  E,  E ).
 combo(step, [P,   [X]|S], [X|S], Ei, Eo) :- !, append(P, Ei, Eo).
@@ -310,5 +317,31 @@ sjc(Name, InputString) :- phrase(joy_parse(E), InputString), show_joy_compile(Na
 expando,    Body --> [Def], {def(Def, Body)}.
 contracto, [Def] --> {def(Def, Body)}, Body.
 
-% phrase(expando, ExprIn, ExprOut).
+% Apply expando/contracto more than once, and descend into sub-lists.
+% The K term is one of expando or contracto, and the J term is used
+% on sub-lists, i.e. expando/grow and contracto/shrink.
+% BTW, "rebo" is a meaningless name, don't break your brain
+% trying to figure it out.
 
+rebo(K, J)      -->    K   ,                         rebo(K, J).
+rebo(K, J), [E] --> [[H|T]], !, {call(J, [H|T], E)}, rebo(K, J).
+rebo(K, J), [A] --> [  A  ], !,                      rebo(K, J).
+rebo(_, _)      --> [].
+
+to_fixed_point(DCG, Ei, Eo) :-
+    phrase(DCG, Ei, E),  % Apply DCG...
+    (Ei=E -> Eo=E ; to_fixed_point(DCG, E, Eo)).  % ...until a fixed-point is reached.
+
+grow   --> to_fixed_point(rebo(expando,   grow  )).
+shrink --> to_fixed_point(rebo(contracto, shrink)).
+
+
+% format_n(N) --> {number(N), !, number_codes(N, Codes)}, Codes.
+% format_n(N) --> signed_digits(Codes), !, {number_codes(N, Codes)}.
+
+% signed_digits([45|Codes]) --> [45], !, digits(Codes).
+% signed_digits(    Codes ) -->          digits(Codes).
+
+% digits([Ch|Chars]) --> [Ch], {code_type(Ch, digit)}, digits(Chars).
+% digits([]), [Ch]   --> [Ch], {code_type(Ch, space) ; Ch=0'] }.
+% digits([], [], _).  % Match if followed by space, ], or nothing.