Blue Eye Macro

I got a cool idea, don't know if it excists already but here it goes.
If there was an option that we could select a type of pixels and put a colored ball on it that puts that pixel in the ball type group. Then we could program that the pixels wich are in the same balls group should stick to eachother, this way we make a smart detection system that will put the right parts to eachother.

Put a file with my comment to show the idea I mean


edit: I think I didn't really get how this tetris worked haha, I was thinking that you needed to put the same colors together