One out of three

I recently posed one of my favorite questions of all time to a student I’m tutoring. He’s something of a natural, and got it remarkably quickly. I personally spent hours on it the first time I heard it, and then years to understand all the subtlety of it. And yet, it’s possible that a group of kids with no mathematical training might be able to solve it out of necessity on the playground.

So here’s the question: you have a fair coin, meaning it’s equally likely to come up heads or tails. How can you design a game that involves only flipping the coin, that you have a one out of three chance of winning?

Every time I pose this, someone ends up coming up with a solution I’ve never thought of before. I’d love to see if any readers have new solutions for me.

[Note: I posted this question here. You can check out people’s responses.]