Red + Blue = Purple
Red + Green = Yellow
Blue + Green = Cyan

Yellow + Cyan = Green
Yellow + Purple = Red
Cyan + Purple = Blue

Red + Blue + Green = White
Cyan + Purple + Yellow = White

Pairs - Circle two or more pairs of same shapes/color
Triple - Circle two or more triples of same shapes/color

All Color - Circle one star of every color
All Shapes - Circle one star of every shape

All Clear - Circle all stars on the screen at the same time.

Stay tune for more tips!