Simpler Fibonacci function

I am new to functional programming and teaching myself Haskell. The canonical Haskell "fib" function (e.g. as presented in the "Gentle" tutorial) is: fib = 1 : 1 : [ a+b | (a,b) <- zip fib (tail fib) ] This seems, to be polite, a bit overly complex. By comparison, here is a simpler version: fib x y = x : fib y (x+y) For example, fib 1 1 => [1,1,2,3,5,8,13,21,...]. Is there a reason why the canonical fib function is so complex? If not, would it be possible to use a simpler version in the tutorial? Thanks. -- Brian