"Moon" also comes as a special feature of the Biophilia App for iPad, iPhone and iPod touch, available through In-App Purchase.

Björk's Moon app is a song and music sequencer inspired by similarities between cycles in music and cycles of the moon and tides. It also contains an animation, a scrolling music notation and an essay exploring Björk's ideas about cycles in music and nature.

The app opens with a musical sequencer arranged as pearls strung out like ribs projecting from a central spine. Each pearl sounds in sequence and can play any note from the song's pitch collection. Fluid in the spine rises and falls with the moon above and tides below, and pearls play when fluid spills out from the spine and washes over them. In song mode the phase of the moon changes with the song structure. In instrument-mode drag your finger across the pearls to change their phase and you change their corresponding pitch. Tap on the moon to change its phase, the amount of fluid it pulls up through the spine, and the number of pearls activated by the fluid.

Biophilia is Björk's most interdisciplinary project to date, comprising a studio album, an app, a new website, custom-made musical instruments, live shows, and educational workshops. Björk recently completed her residency at this year's Manchester International Festival where Biophilia received its world premiere. She will return to the U.K. to headline Bestival on September 11 before taking the Biophilia show to Iceland, where she undertakes a residency of eight shows at the brand new Harpa Concert Hall, including two nights as part of the Iceland Airwaves Festival starting October 12.