The staccato beat of conga drums rises over the deep voice of a bass guitar and the higher trills of the timbales and piano. Head dancer Evan Margolin and his bevy of experienced instructors lead students in classes that take beginners through basic footwork and salsa rhythms, with intermediate and advanced sessions offering salsa aficionados more challenging instruction. The social class structure—partners rotate throughout every session—creates a low-pressure learning environment and keeps dancers from scrambling to locate a partner or human-shaped tupperware container. The one-hour beginner classes are mostly filled with salsa novices and new dancers, and Dance SF's experienced and engaging local salsateers are patient and friendly when showing new students how to bust well-timed moves. During intermediate classes, which require six months or more of social dancing experience, students focus on timing and cross-body leads with turns. After some evening classes, new dancers are invited to join an all-night salsa party where they can put their new moves in practice. Students should wear comfortable clothing, which includes dancing shoes, but does not include rear-flapped onesie pajamas.