Added O(1) fib in comment

fib.fs

@@ -12,4 +12,13 @@
 	+
     then ;
 
-: main 34 fib drop ;
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+: main 34 fib drop ;
+
+\ The problem with fib is that it really is O(1)...
+0 [IF]
+    5e fsqrt fdup 1/f fconstant /sqrt5
+    1e f+ f2/ fln     fconstant gbase
+    : fib ( n -- f )
+	dup s>f gbase f* fdup fexp fswap fnegate fexp
+	1 and IF f+ ELSE f- THEN  /sqrt5 f* ;
+[THEN]
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