One pre-20th century example of found percussion is the use of cannon (usually loaded with blank charges) in Tchiakovsky's 1812 Overture. John Cage, Harry Partch, Edgard Varèse, and Peter Schickele, all noted composers, created entire pieces of music using unconventional instruments. Beginning in the early 20th century—perhaps with Ionisation by Edgard Varèse—which used air-raid sirens (among other things), composers began to require that percussionists invent or find objects to produce desired sounds and textures. Another example: the use of a hammer and saw in Penderecki's De Natura Sonoris No. 2. By the late 20th century, such instruments were common in modern percussion ensemble music and popular productions, such as the off-Broadway show, Stomp. Rock band Aerosmith used a number of unconventional instruments in their song Sweet Emotion, including shotguns, brooms, and a sugar bag. The metal band Slipknot is well known for playing unusual percussion items, having two percussionists in the band. Along with deep sounding drums, their sound includes hitting baseball bats and other objects on beer kegs to create a distinctive sound.