Mission Bay Fountain

After getting the car back this morning I went to collect a chair that S had bought from the online site, TradeMe. On the way home, I paused at Mission Bay where the fountain was playing, and one mother and child were playing in the fountain, and a line of people on the other side of the fountain were playing at something. Not sure what it was but they were following instructions of a ?leader who often got them to clap their hands in unison. Once, each time.