Fibonacci


fibs :: [Int]
fibs = 0 : 1 : [ a + b | (a, b) <- zip fibs (tail fibs)]
Fibonacci

Apparently this might get added to Factor 0.90: http://useless-factor.blogspot.com/2007/07/thats-dirtiest-macro-ive-ever-seen.html

So something like "tuck dup" can be rewritten as "xy-yxx". It's a lot easier to track what you're doing when you have long chains of stack manipulation.