I don't know where this idea came from, but I figured I needed to use all the background papers I've been painting, so I just cut 2-inch squares and arranged them in rainbow order from the top left to the bottom right of a canvas, "et voila!" This piece is 18 x 24 inches.
Here are some close-ups:
This will now hang in my daughter and her boyfriend's apartment, right above their giant TV. It reminds me of giant TV screen pixels!