With over 700 command blocks, 120 different combinations, and much fun, you should probably play this map. This entire project has taken me many months, and I just decided to post it now. Why? Because I'm not feeling lazy right now. Plus I already had some screenshots. I'm also 90% sure the world wasn't corrupted, which is why I might not have posted it before. Regardless, the way it works is this. Every place has a "color check" line of command blocks, testing for what color the block is. Then upon pressing a button, it tests the test color placed by the color check, then places the correct block. The reason why we can't just test and place, and why we have to test test place is because if you just do that, it leaves you with duplicates of the same color, rather than swapping colors. For example, pretend we have spots 1 & 2 with corresponding colors red & blue. If we tried Test place, it would test 1, and see it as red, placing red in spot 2. Then after testing 1 it tests 2 (Now Red), and sees it as red, placing red in spot 1. See the problem? Even we tried executing the commands at the same time, one always ends up executing first. However we can try our other method, test test place. Lets say we have spots 1a & 2a with placeholders 1b & 2b. It first tests 1a, which is red, so it changes placeholder 1b to red. Then it tests 2a and changes 2b to blue. Then it tests 1b and changes 2a , and it tests 2b and changes 1b. Because there is an extra step, both tests get to test the placeholders before the place is executed, and the placeholders change, allowing for proper swappage of the colors. This of course requires a lot of command blocks, hence when it is finished, there will be over 700 of them.