Yep I agree, as it is the concept is pretty limited, just wanted to test an idea. I was thinking about changing the rules so that the active color is the solid one, instead of the two others. This would allow changing color while inside another color. But I never planned to push it further, not worth the time, as you said there arent many puzzles one can think of with this concept.
As for the color cycle, it's RGB (red then green then blue) as in the title :p
Thanks for the input !