Creative people find inspiration in anything. A walk in the woods means you need to make a cake or a bracelet. Do you remember Scarlett O’Hara, who won over Rhett Butler with a dress made of curtains?

“Make something people want.” That’s the famous Y Combinator slogan—and the results speak for themselves. Over the years, YC has launched some of the most iconic startups of our time, including Airbnb ...