After adding shiny tape to the cart I started working on diffusing the LEDs. The circuit boards I designed don’t scatter the different colors LEDs out very much. It was a sacrifice I had to make in order to keep costs down with single sided copper clad boards. Diffusing will make blue and red produce purple, instead of two discrete spots of each colour.
This is a lighting diffuser panel from Home Depot. It’s the thing you see over the lights in a lot of office buildings. They gave it to me for free because it was broken!