Bauhaus artist Ludwig Hirschfeld-Mack designed these Optischer Farbmischer (optical color mixer) tops in the early 1920s. Reproductions by Naef are available from Fawn & Forest for $49. From the product description:
The first production of this toy started in 1977. The "Bauhaus Optischer Farbmischer" shows us how the rotation of a top brings about a color blend. Varying aspects of color theory are deomonstrated on the reverse of the inter-changeable color discs Not for children under 3 years old.
Bauhaus tops (Fawn & Forest, thanks Kelly Sparks!)