MorganS:
Great, except 2, 4 and 7 aren't PWM pins on an UNO and they won't fade. 3, 5, 6, 9, 10, 11 would be a better choice if you have an UNO.
True indeed. Of course, it wasn't intended as full tested solution, just as a pointer to set the OP in a possible direction. I won't edit it now but I'd also reduce the maximum PWM rate to fit in a single byte (as a Uno - if that is what he has got - requires).
He also has to tell us a bit more about what he is up to, and maybe even finish off the sentence at the end of his post.