Sequence is a music ecosystem, a virtual petri-dish where every swimming organism is created and represented by a step-sequencer pattern. You bring the creatures into existence by making musical loops, and then change their form and behaviour by tweaking elements of sound including octave, melody, volume, even the waveform itself. One-by-one you can create and add more creatures to the soup, each playing its own part of the greater musical composition and then, when you think you have a song that matches your expression, you can create a link to save it and share it with others. There's a video here that will show you how it's done.