A flute is a musical instrument that produces sound when a stream of air is directed against the edge of a hole, causing the air within the body of the instrument to vibrate. Most flutes are tubular, but some are globular or other shapes. Some flutes are played by blowing air into a mouthpiece, which directs the air against the edge of a hole else-where in the flute. These instruments, known as whistle flutes, include the tubular recorder and the globular ocarina. Other flutes are played by blowing air directly against the edge of the hole.