By Tyler Aquilina
November 11, 2019 at 09:30 AM EST

Knock-knock-knock. “Penny?” Knock-knock-knock. “Penny?” Knock-knock-knock. “Penny?”

The Big Bang Theory forever embedded that sound in its viewers’ brains over the course of its 12 seasons, as Sheldon (Jim Parsons) deployed his signature way of knocking countless times. Though the hit sitcom has now concluded, fans will have the opportunity to revisit their favorite moments and episodes to their hearts’ content with the new complete series box set, available Tuesday, Nov. 12 on DVD and Blu-ray. (Not to mention when the series arrives on HBO Max next year.) In the meantime, EW has an exclusive clip from the set’s new bonus features: a journey through the series via Sheldon’s knock.

The clip features many of the running gag’s most memorable variants: Sheldon’s rapid-fire knocking while dressed as the Flash, speaking with the aid of a computer voice program, and calls for not just Penny (Kaley Cuoco) but LeVar Burton, Wil Wheaton, and “all my friends.”

Check out the exclusive clip above.

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