Rhythm Necklace is an iOS app, created in collaboration with Sam Tarakajian.
It is available on the App Store. You can read more about it here.

“A simple, intuitive tool for building up polyrhythms and taking them apart, layer by layer.“ --wired.com

Rhythm Necklace is a digital sequencer that allows you to create and perceptually mix geometric patterns according to grouping principles found in cognitive science and gestalt psychology. Although grounded in scientific research, examples of these grouping principles have been found in popular music all over the world. This unique new tool encourages intuitive composition from an advanced perceptual standpoint without the rigidity of traditional musical rules or knowledge.

This project explores auditory perception as related to Euclidean algorithms, the mathematical properties of which are useful in fields as varied as crystallography and radio astronomy. These algorithms are also relevant in ethnomusicology, where they take the form of rhythm necklaces—circular representations of what is ordinarily thought of as a horizontal timeline. These necklaces are a particularly interesting foundation for an exploration of perception; their repetitive cycles and interlocking modular nature make them an ideal constant for highlighting the tricks that our ears play on us.

The idea for this sequencer was based on the work of Godfried Toussaint, Albert S. Bregman, and E. Bjorklund. The first prototype was built in Max/msp, with additional JavaScript and Ruby by Beau Sievers.