@DrWizard I agree with @Deva_Rishi here. I think it may be possible to speed up the code you posted somewhat, but it will probably make very little difference overall because other parts of your sketch will be far slower, in particular the .show() which takes a fixed time for a given length of strip. The only way to speed up the animation may be to skip frames, in essence, by calling .show() a fixed number of times per second, resulting in some of the frames your code is drawing never actually being sent to the strip.