Isle of Tunes lets you create music/tunes by placing isometric tiles like cars (those are the 'generators by moving amongst the other tiles), houses, trees, lanterns and other things. Also allows loop-creation, adjustment of certain tones by clicking on the tilesets and more..

You can save your personal creation and return to it or share it, isleoftune.com/ (Skip the 'now for iPad' information to enter)