diff --git a/thun/thun.pl b/thun/thun.pl
index 1fbc637..5d74b03 100644
--- a/thun/thun.pl
+++ b/thun/thun.pl
@@ -104,7 +104,7 @@ thun([Unknown|E], Si, So) :-
     damned_thing(Unknown),
     write("wtf? "),
     writeln(Unknown),
-    So = [[Unknown|E]|Si].
+    So = [Unknown|E]-Si.
 
 damned_thing(It) :-
     \+ literal(It),
@@ -144,6 +144,8 @@ literal(_=\=_).
 Functions
 */
 
+func(words, S, [Words|S]) :- words(Words).
+
 func(cons, [A, B|S], [[B|A]|S]).
 func(swap, [A, B|S],  [B, A|S]).
 func(dup,     [A|S],  [A, A|S]).
@@ -298,6 +300,14 @@ assert_def(def(Def, Body)) :-
 :- assert_defs("defs.txt").
 
 
+words(Words) :-
+    findall(Name, clause(func(Name, _, _), _), Funcs),
+    findall(Name, clause(combo(Name, _, _, _, _), _), Combos, Funcs),
+    findall(Name, clause(def(Name, _), _), Words0, Combos),
+    list_to_set(Words0, Words1),
+    sort(Words1, Words).
+
+
 /*
 Compiler
 */