The term 'avant-garde' comes from the army. It is a name for the troops, who are the first to explore unknown territory. The term also appears in art and is used in both jazz and classical music as a name for the most daring styles. In pop music, avant-garde artists mock the laws of pop songs. Although an avant-garde composer prefers to work without rules, different rhythms and keys are the rule rather than the exception in his music. The sixties were a golden age for the avantgarde. Many rock bands improvised on it. Artists like Frank Zappa, Captain Beefheart and Soft Machine romped with free jazz and atonal music. Avantgardists were also the first to pick up new instruments (synthesizers) and techniques (cut-up, sampling).