This could be a lesson in harmony as the filled in colored circles could be made to match the magazine circles next to them.
Rainbow Salt Tray 9
Try a little color bag sorting!
Simple color mixing for kids and toddlers.
outdoor color match
Practical Colors Tutorial by KelliRoos.deviantart.com on @deviantART
paint a rainbow with a sponge!
LOVELY!! color sorting tray
Color Treasure Hunt