In the course of the preparation weeks before the Physics & Music workshop, students from the technical university started to build a so called laser harp - an instrument where 13 lasers beams form 13 light-strings. When you put your hand inside a laser beam, the connection to a sensor is interrupted which gives an MIDI command you can process further with different software programs. As the 13 input channels are programmable freely, the laser harp gives a full playground for everybodys creativity.