Subject: Please explain the formation of the colors and the shapes in my spinning to

     I have a spinning top that has three circles on top of it. Each 
circle is divided equally into three colors:(1/3) red,(1/3)yellow,and 
(1/3)blue. When the top spin, the three circles on top spin 
independently creating a visual effect of color variation. The colors 
appear to expand from the center outward displaying the following 
colors: red, purple, blue, soft orange, yellow,and a soft yellow (kind 
of closer to green, but not really green). 
      My questions are":                                              
           How do we perceive the different colors by the spinning of 
the three disks? Why are we not able to perceive green when we see 
other colors? How are the concentrical circles formed?            
      I will greatly appreciate your assistance since my fith grade 
students are inquiring about our peculiar toy.                        
                                            Sincerely, Ms. Campos

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