gistfile1.txt

import Control.Exception
import Control.Monad
import Control.DeepSeq

main = forM_ (permute "laeioslaeioslaeios") putStrLn

leet :: Char -> String
leet 'e' = "e3"
leet 'a' = "a4"
leet 'A' = "A4"
leet 'o' = "o0"
leet 's' = "s5"
leet 'S' = "S5"
leet 'i' = "i1"
leet 'I' = "I1"
leet 'l' = "l1"
leet 'B' = "B8"
leet x = [x]

permute :: String -> [String]
permute [] = return []
permute (c:cs) = [ c':cs' | cs' <- permute cs, c' <- leet c ]