Ordinarily I would not post to a list when I've got a program running. But I've found learning Haskell so tough (this is my 4th try in the last two years) that I feel I have to bore everyone with my first non-trivial program. It is Newton's method adapted to give the square root of a number. And all in just one line which I think is an amazing demonstration of the power of Haskell. And it took no more than a couple of minutes to write (directly to the screen too as opposed to the usual many paper drafts with C). It works too, correct to 13 decimal points on my GHC system It is :- my_sqrt t = last (take 20 (iterate (\n -> n/2 + t/(2 * n)) t)) It is a bit crude though. 20 iterations is a bit arbitrary. I don't suppose there is a easy way to iterate until the results stop changing.