24-Piece Wooden Colorful Kaleidoscope, Colorful Learning Educational Toys. Crafted Of Hardwood High-Quality Non-Toxic Material. 

• 【Color See】Through Effect Of Light Exposure, Color Recognition, And Color Superimposition And Transformation Effect Solid Wood Board That Is Easy To Grip
• 【Colored Lenses】Different Colors Of The World, Observe Different Colors Of The World Through Lenses Of Different Colors, Superimposed Lenses To Produce New Colors, And Enhance The Baby's Cognition Of Colors
• 【Creative Building】 Stimulate Baby's Creativity, While Building Shapes, Exercise Baby's Imagination And Improve Hands-On Ability

You can hold up 2 primary colors to the light and see the secondary color.