Use the arrow keys to move the switcher line thingy, and space to cycle the colors of every circle under the line. For debugging, you can click any circle to cycle its color, or press the N key to solve the puzzle instantly.
This puzzle is almost always unsolvable due to parity errors, similar to randomly placing stickers on a Rubik's Cube. The four numbers on the left show the "parity" of the puzzle. They are calculated as follows: (blue = 0, green = 1, red = 2, yellow = 3): (upper left + middle) - (left + top) mod 4 (upper left + right) - (left + top right) mod 4 (upper left + bottom) - (bottom left + top) mod 4 (upper left + bottom right) - (bottom left + top right) mod 4 They cannot be changed by the normal puzzle moves, and the puzzle is only solvable if they are all 0, so the puzzle is only solvable in 1/256 cases. This could be fixed by shuffling it using puzzle moves rather than randomizing each individual circle, or by adding additional moves (such as a shift) to allow the puzzle to be solvable in all circumstances. Doing both would probably be coolest, since it would add a lot of depth to the puzzle.
