John Bedford (Modojo): The best puzzle games take an effortlessly simple concept and then spin it out into new and intriguing ways - and Harmony is no exception. All you have to do here is rearrange the handful of tiles on each screen, turning them from a jumbled up mess into the solution you're presented with.
You swap individual tiles around by tapping on one to begin, and then tapping on another to switch them over. Certain tiles can only be moved a certain number of times though, and you must use up every last turn between the start of the challenge and the eventual solution. It's trickier than it sounds.