Create a circle. One person in circle picks another random person and claps at them. The person that was singled out with the last clap immediately picks another random person out, by clapping at them. Clapping flies back and forth across circle. Ideally there's constant clapping noise. Focusing can be made harder by pointing rather than clapping to the next person in turn.
Instead of clapping, use eye contact (or eyes closed telepathic communication).
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