[Haskell-cafe] Properties of monads

Hello, I am writing some toys programs to learn and try to apply Monads properties (without success, I must say). Although I spent half a day on this code: http://hpaste.org/3957 I couldn't simplify (shorten) getStrip function. After reading "Doing it with class" ( http://www.haskell.org/all_about_monads/html/class.html ) I had an impression that I could "collapse" cases using some Monads properties. But maybe I misunderstood something. Can anyone look at it and give me a pointers?? (I don't mind if the code becomes unreadable a bit.) Thank you, Radek.