The numbers that make up today’s date Dec. 5, 2013, happen to be whole numbers that can form the size of a right triangle, and the National Museum of Mathematics (MoMath) in New York City is throwing a party tonight to celebrate. If you need a quick high school math refresher: the numbers 5, 12, and 13, satisfy the Pythagorean Theorem (a² + b² = c²), meaning the legs of the two shorter sides of a triangle squared and added up equals the square of the triangle’s longest leg. (Whoa.)
MoMath, which will celebrate its first birthday on Dec. 15, has invited math fans to gather in Manhattan’s Flatiron district to demonstrate that the proportions of the iconic Flatiron Building roughly form a right triangle.
“We’re just going to have people line up with identical glow sticks, and we will discover that it takes 75 glow sticks on [the Flatiron Building's] short side, 180 for the 5th Avenue side, and 195 for the Broadway side, and if you divide those numbers by 15, you get 5, 12, and 13,” Glen Whitney, co-founder and executive director of MoMath, tells TIME. ”The next time these particular three numbers will be part of a date is 2105, 92 years from now. And the next date that has numbers that form a Pythagorean triple is Aug. 17, 2015 — 8, 15, and 17 also satisfy the theorem.”
The festivities begin in the public plaza on Broadway between 22nd and 23rd streets at 6:45 p.m.
MORE: Happy 11/12/13!