Walls & Ceiling-Diffusion or Absorbtion?

Everest's Master Handbook of Acoustics shows enough info/pix for a reasonably experienced DIY'er to build poly's - BTW, have you watched America's Funniest Videos recently? Guess what they have on their walls - If you're into overpowering effects, think what that wall would look like with alternating colors - or, as they've done, accent lighting for shadow effects... Steve