5. Jack & John

Jack gave John the following challenge: “If you sit down in that chair, I bet I can make you get out of it before I run around the chair three times,” he said.

“Aw, that’s not fair,” John said. “You’ll just prick me with a pin or something.”

“Nope,” Jack said. “I won’t touch you, either directly or with any object. If you get out of the chair, it’ll be by your own choice.”

John thought, accepted the challenge, and then…., Jack won the bet. How did he do it?