Late-night comedy writer Joe Toplyn was on David Letterman’s writing staff when the famous Top 10 list was born, and he shared stories from the start of the long-running institution with HuffPost Live’s Josh Zepps on Monday.

It took a little experimentation before the writers landed on the structure that dictates the nightly lists fans are familiar with. After the very first top 10, which Toplyn described as “meta on meta,” Letterman’s staff “figured out the way to do these was to think of the top 10 list as a joke with 10 punchlines.”

After discussing his book Comedy Writing for Late-Night TV, Toplyn dove into what he called “nerdy comedy” as he explained to Zepps how the the jokes are carefully ordered for optimum laughs. He shared several insights into how to decide which joke is read when, including this one:

Number six we used to try to make a particularly big laugh because there are two screens — the first five would be on one screen, the second five would be on another screen. So just to give the operator of the character generator a second to push the right button, we’d get a big laugh on six, and that would give her a few seconds [to switch to the next screen].

Hear more about the top 10 list in the clip above, and watch the full HuffPost Live conversation with Joe Toplyn below.