The Story Behind the 99PI Challenge Coin

So you finally got your 99% Invisible challenge coin, but are not quite sure what it all means. Before your next coin check, brush up on both sides of your newly-minted coin by listening to these ten excellent episodes from our archives. First, some context for the coin itself; next, the origins of the mantra on its front; finally, all eight symbols on the back, listed clockwise and starting at the top.

For 99PI fans, this is pretty damn cool (I am proud to say that I would pass a coin check). But this also serves as a great primer for the show as a whole.