In a regular simul, no chess clocks are used. The boards are usually arranged in a large circle or square and the exhibitor walks from board to board in a fixed order. Each individual participant is expected to make a move when the exhibitor arrives at his/her board. The exhibitor may pause briefly before playing his/her move but will typically attempt to avoid lengthy pauses because too many such pauses will cause the exhibition to continue for an extended period. Longer exhibitions increase the risk of fatigue-induced blunders on the part of the exhibitor.
During his 1964 exhibition tour, Bobby Fischer barnstormed the US and Canada from coast to coast and his entertaining lectures, high level of play and personable manner won him many new admirers.
* Diagram - Fischer (White) to play with both queens en prise
😎 Video - Beth v 12 players from The Queen's Gambit (3:05)