Complex Equiangular Lines: The Unusual Shapes of Quantum Physics

How many intersecting lines can you draw such that the angle made by any pair is the same as the angle made by any other pair? What if you try in 3 dimensions, or 4, or 5? What if you let your coordinates become complex numbers? And what does all this have to do with quantum probability?!

As the kids say, “Like, quantum and subscribe!”