"On a very stormy day, I noticed how the hollow mast of a street sign generated a sound. The strong wind blew over the open upper end of the pipe. For the M-Pipes I have investigated the phenomenon of the air sidestream. The rough blown sound is generated with specially built valves, which blow at the opening at specific angles, and is reminiscent of a transverse flute or at times even the deep sound of a cello. It is the same basic principle as the organ pipe, however, the execution is very different. The pipes are open and made of drainpipes of rain gutters."