Echo is a musical puzzle game that I made with my musician/programmer friend Chris Deaner. We released it in 2014 as both an web game and an iOS app (using Phonegap).
The objective is to match a given musical pattern by creating loops while avoiding collisions. The loops combine to make tracks and tracks combine to make songs. While the game starts off relatively easy, it quickly ramps in complexity with more pieces and more intricate puzzles.
The online version is still up (lots of people still playing it and very few people beating it), but the version in the app store is no longer available.