Shimon is the name of the bigger marimba playing robot and the Shimis are the smaller robots. The smaller robots do indeed autonomously generate dance moves to

Shimon is the name of the bigger marimba playing robot and the Shimis are the smaller robots. The smaller robots do indeed autonomously generate dance moves to the music, but they are also improvising. Some parts are precomposed (bass lines, drum parts, chord changes), but the lead robots during each section play music that is machine generated.