"Engage in other silent activity"

Play air guitar after the Pledge of Allegiance to be legal.

Everyone needs to find something quiet to do. (Indiana (State) Law)

Pray ...Ok Meditate …criss-cross applesauce let your inner Buddha-eye see… …itself/you.

But then again, “engage in other silent activity” …like quiet chicken dancing, faux surfing, or doing a full body wave like you are a flag. It is recommended and legal; therefore, it is grand.