Lovely execution! Very relaxing and fun educational game. I only got tripped up when I realized I didn't have to paint all 3 curls, and was allowed to mix just two colors.
It would have been cool if there was a way to actually simulate Newton's spinning disc effect! Maybe some sort of 2D shader which could actually blur the colors together or something. It worked really well as you have it now, until I had to mix brown - and you really notice the jump cut from colors -> brown while it's spinning. The art is super clean and pleasing to the eye. Very well done overall building the aesthetic and atmosphere for the game. Excellent work!! I got to the end, and it was quite satisfying to complete it.