When I taught junior high, we watched a video about animation and made
simple thaumotropes using two simple pictures on a circle of stiff paper
(bird on one, empty cage on the other was the sample on the video).
We stapled them together on either side of the end of a pencil. Two staples
does the trick if they are close enough to the pencil to keep it from
sliding. You hold the rest of the pencil between your two palms and twirl it
back and forth, making the pictures combine. Should work with color mixing