Expressy is the prototype of the tool that enables an Android application to use live stream of accelerometer data from Pebble Classic smartwatch in order to add additional degrees of freedom to touch screen events. The original idea was described in the paper "Expressy: Using a Wrist-worn Inertial Measurement Unit to Add Expressiveness to Touch-based Interactions" by Gerard Wilkinson, Ahmed Kharrufa, Jonathan Hook, Bradley Pursglove, Gavin Wood, Hendrik Haeuser, Nils Y. Hammerla, Steve Hodges, Patrick Olivier at CHI 2016, San Jose, CA, USA.