Thanks for the comment! You can navigate through the tiles with the keyboard already (arrow keys :D). As for the linux build issue, I also use linux myself and didn't have any problems (and it uses a bundled java version so really not sure about the problems there). As for the challenge part, it is understandable and yeah I agree the counter at the top really made things easier than it should have been since the main way to know if the tile was in its correct rotation was supposed to be looking at it and checking (there is a "ghost layer" above the tiles that shows their correct rotation).