CHECK OUT OTHER AWESOME DESIGNS HERE! Pythagorean Triple Day is here and you need this t-shirt. The last *primitive* pythagorean triple day was 5-12-13, and the next one won't be until 7-24-25. Get your shirt now to arrive before August 15, 2017. Some people call this pythagorean theorem day, and that's OK. Perfect gift for math geeks, or just geeks in general.