This isn’t quite what I had envisioned. I had some different ideas in my head (a more sunburst pattern, perhaps more like a sunflower). But then I started playing with these circles and the round lines they made.
Then I simply filled in the colors and spent about 15 minutes looking for the effect I wanted. I was sorely disappointed by all of the different effects. Stained Glass, Ripple, Wave, none of them gave the effect I wanted. This final effect is a Radial Blur (on the colored boxes, not on the grid, which I did on a separate layer). It’s not at all what I wanted, but I was thrilled by the result.