The primary problem for the diffuser was to allow room for the LED light to become ambient light within the system of the diffuser.  At close range, LED light was still too differentiated to allow colors to mix well, regardless of the diffuser (anything from crumpled paper to a carved-out apple).  My solution was to create a distance buffer between the diffuser, a ping-pong ball, and the LEDs.  This distance was provided by a lint roller.

For the interface, I mapped the keys as follows:

RED GRN BLU

[1] [2] [3] <-- Full on

[Q] [W] [E] <-- Increase 32

[A] [S] [D] <-- Decrease 32

[Z] [X] [C] <-- Full off

*update* Attaching source code, images. (Apologies--the source code is not formatting properly on the blog. Also, the colors are not well reflected in the pictures, but they work well "live".)