forward is f ( n --> n )
[ dup 0 = if done
dup 1 - recurse f - ] is m ( n --> n )
[ dup 0 = iff 1+ done
dup 1 - recurse m - ]
resolves f ( n --> n )
say "f = "
20 times [ i^ f echo sp ] cr
say "m = "
20 times [ i^ m echo sp ] cr