https://www.wired.com/story/these-bacteria-ate-their-way-through-a-really-tricky-maze/

Trung Phan’s science experiment began with a dare. His boss, Princeton University physicist Robert Austin, challenged him to design a maze that Austin couldn’t solve.

To be sure, the challenge was just a thought experiment—Phan wasn’t about to actually start planting Versailles-scale hedges and throw his boss in the middle of it. But Phan, Austin’s graduate student, took the assignment to heart. He gave Austin a few easy puzzles to start, to learn Austin’s maze-solving strategy. “When he hit a dead end, he just traced his path back, which is a very traditional way to solve a maze,” says Phan. “So my idea was: How about a maze with no dead ends?”