A Coloring Structure
We will consider a structure for a collection of colors that will provide
a scheme for designing a web page.
Conditions for a Coloring Scheme Structure
 Each scheme will have exactly 3 colors.
 Any two coloring schemes together will use exactly
5 colors.
 Any two colors determine a unique scheme.
 There are at least two schemes.
Here are two examples:
Notice that each structure has 7 colors and 7 schemes!
C 
E 
G 


G 
B 
C 
B 
D 
G 


G 
D 
F 
A 
F 
G 


G 
A 
E 
A 
D 
E 


C 
E 
D 
B 
F 
E 


D 
A 
B 
A 
B 
C 


C 
A 
F 
D 
F 
C 


B 
F 
E 
The question we have is:
Are there any color scheme
stuctures that have more or less than 7 schemes made from 7 colors?
That is, is there some
special relation between these color scheme structures and the number 7?