Brian Eno -- best known for work as a producer and ambient musician -- has released a second iPhone application, developed with the help of designer and musician Peter Chilvers. Called Trope, the app lets users create their own ambient music by drawing patterns with their fingers. The shape of each pattern creates a different tone.

Unlike the first Eno app, Bloom, Trope is described as producing darker music that is "more introspective, more atmospheric." Particular moods can be selected from an accompanying palette. The software costs $4, and requires a device with iPhone 2.2 firmware or better. For the sake of fidelity it is recommended that people use either headphones or external speakers, instead of earbuds or built-in speakers.