The rhythmic structure and a basic requirement of all cool and uncool flamenco. Palmas or handclapping help keep time, but it takes practice. I discuss this elsewhere on this web site. Name dropping is not cool unless you know enough, but since nobody can agree on what flamenco is you might as well bluff away. Flamenco is an amalgam of gypsy rhythms and folklore as well as other influences.
Nobody can say for certain, but everyone loves to argue about it.