This is a really nice, relaxing game, with a cool take on the theme. I really love the fact that the triangles turn as you rotate! Personally, expert mode is the definitive way to play, as normal mode seemed a bit easy. If you consider developing this in the future (and I recommend you do, as it would work very well as a mobile game) I'd suggest making the difficulty ramp up as you play.
Very solid game, great job!