Last week, Brian Eno's management company released "Air" to the app store. While it wasn't written specifically by Eno, it was "based on concepts" by him. Trope, on the other hand, was made by Eno and Peter Chilvers.
Eno and Chilvers developed Bloom together, and Trope is very similar to it. It's the same setup, where you tap your finger in different areas of the screen to create sounds that then loop and change over time. Trope uses more drones and pads than Bloom, however, so the music you'll get it quite different and, as the developers say, darker than Bloom. The visuals have also gotten a big bump up, offering much more variation in patterns and colours than Bloom.
Trope is $US4 and you can get it from the App Store now. If you liked Bloom, you'll like this. [Trope (iTunes Link)]