 A joke can be reused in different joke cycles; an example of this is the same Head & Shoulders joke refitted to the tragedies of Vic Morrow, Admiral Mountbatten and the crew of the Challenger space shuttle.These cycles seem to appear spontaneously, spread rapidly across countries and borders only to dissipate after some time.Folklorists and others have studied individual joke cycles in an attempt to understand their function and significance within the culture.