Bifurcation and the logistic mapping

I've been reading Ian Stewart's book Does God Play Dice? The New Mathematics of Chaos, and I got inspired to play about with some of the stuff described therein. You've probably all seen this image before:



The formula that produces it is almost shockingly simple, and yet the behaviour it produces is really quite surprising: yet another reminder that "complicated" is not the same as "deep".

( The maths behind the picture - generally accessible )

Cool, eh?

How I produced the diagrams for the last entry, and a plea for help

( Cut for geekiness )

So, can anyone help me with my Haskell problem? Anyone? Bueller?