Do you have a favorite fractal?

All fractals are cool!  Madelbrot rules!

I guess I find the collatz fractal the most interesting because that's the only one I've run across. I'm pretty sure it's worthless, but its interesting that you can get some sort of fractal representation for the problem. It hasn't led to any progress in the solution though so its probably worthless.

Collatz fractal.  That's interesting, I had not run across that.  Had to look it up on wikipedia. 

Others are cantor dust, sierpinski triangle, Weierstrass function and lots more.  Pretty sure that the Mandelbrot set was around before Mandelbrot came along.