Equiangular lines are lines in space that pass through a single point, and whose pairwise angles are all equal. Picture in 2D the three diagonals of a regular hexagon, and in 3D, the six lines ...
Equiangular lines are an elemental part of geometry. Mathematicians have discovered a tighter limit on the number of such lines that exist in every dimension. Imagine a set of many lines as in a dream ...