Oh, you're the author! I didn't notice and sent you an email, but will repost here:
$ for i in 3 4 5; do f=puzzle.$i; echo $f: $(head -1 $f | wc -c); tail -$((i-1)) $f; ./$f; done
puzzle.3: 1
futz
futz
./puzzle.3: line 3: futz: command not found
puzzle.4: 1
futz
futz
futz
./puzzle.4: line 4: futz: command not found
puzzle.5: 1
futz
futz
futz
futz
./puzzle.5: line 5: futz: command not found
I just wanna note here, for future readers, that this guy cheated in a deliciously naughty way, by registering a custom binfmt handler specifically for puzzle.[345], and deserves to get hit on the nose with a rolled up newspaper.
That's certainly the expected output. Emailed you back. You landed in spam, btw.