 Most Grateful Dead concerts featured an extended segment during the 2nd set of improvisational drumming and percussion by Hart and Kreutzmann who took over the stage as a duo (with occasional guests).This segment was variously known to fans as "Rhythm Devils", "Drums", or conversationally as "the drums", and was usually followed in post-1979 concerts by another extended improvisation by the rest of the band, usually without the drummers, which was known as "Space".The "Rhythm Devils" segment of a Grateful Dead concert almost always segued out of a full-band song, and the "Space" segment almost invariably would segue into the beginnings of another full-band song as the drummers resumed their seats with the rest of the band.