Taking two copies of the same record (or different records if you're really good at it), and creating a new drum pattern by re-arranging and syncopating the beat. Live. Is very difficult to do in a way that sounds any good. Beat juggling has developed from "deck to deck" or "quick mixing" techniques, and is the staple of DJ battle competitors' routines. Good jugglers included Rob Swift, Shortkut, Babu and Vinroc.