In just 10 years, Shake Shack has become NYC’s most iconic burger brand and turned founder Danny Meyer into a multi-millionaire.

We’ve all heard the story of how Shake Shack started as a humble hot dog cart in Madison Square Park. But what you might not know is that Meyer and CEO Randy Garutti originally sketched the concept for the chain on the back of a napkin.

While many of the ideas turned into the menu that we know and love today—the Chicago dog and crinkle-cut fries were always part of the blueprint, as Eater points out—there are also some that ended up on the cutting-room floor, like a tuna burger and fresh pineapple juice.

Check out the sketches below, and remember to keep all of your back-of-the-napkin musings—you’ll be glad you have them when you make your first million.

shakeshack_napkin_1

 

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[via Eater]