Instrument A is a composition and performance environment, controllable using only a single-button interface that can be adapted to each user’s needs (e.g. adapted mouse, head interface, space bar). After opening the program for the first time, the user can begin a new composition by selecting one of 49 available loops as the basis of his or her composition. This loop can either be heard or silent during the final performance, but it will give each song its bpm and thus cannot be changed afterwards. The user can then add more loops or build new ones using the 105 samples available, through an interface similar to the one developed for Políssonos. After all the loops are laid out, the user can perform the song by triggering and layering different loop combinations and by freely playing the notes within a loop. Each song can be saved for future performances or subsequent compositional work and each performance can be recorded live as an audio file. The sounds for Instument A were selected from samples recorded at Casa da Música, from freesound.org and from Rolf Gehlhaar‘s personal library (please check the manual below for a complete list).