WHO STARTED THE MOTION?
One person volunteers to be "it." They either leave the room or close their eyes or turn their back on the group. Select one person to begin a definite motion. The rest of the group copies that movement. "It" goes to the center of the group and tries to see who changes the motion to a different pattern. The person who "changes" the motion should do so when "it" isn't looking. Give everyone a chance.