Clap Clap Clap-clap-clap. I believe every classroom in America has heard this pattern before. The teacher does it. The students mimic it. If it doesn’t work the first time (aka, only half the attention is grabbed) I usually do a second pattern and change it up: Clap Clap stomp-clap-clap. If I am in a musical situation, or a few students giggled, I may go on a tangent of various patterns because, hey, rhythm is fun!