The most elegant mathematical joke you'll see today. That right triangle with sides labeled "i", "1", and "0" is essentially Euler's identity (e iπ + 1 = 0) disguised as the Pythagorean theorem. In spacetime diagrams of special relativity, we use similar mathematical tricks with imaginary numbers to represent time coordinates. Whoever created this managed to unite complex numbers, geometry, and relativity in a single triangle that technically shouldn't exist. The math department probably has this framed somewhere between their "√-1 2³ ∑ π" joke and their collection of physicist tears.