Shake it like a polaroid picture: Brother/sister duo Wild Belle may defy concise descriptors, but who cares when the music is this danceable? The pair's debut album, Isles, is a world-friendly affair that draws on psych-pop, electronica, reggae, funk and jazz for a beat-centric sound catchy enough to make mountains move. Wild Belle plays Emerald Lounge on Sunday, Oct. 20.