A picture of the E8 root system. The E8 root system consists of 240 vectors in an eight-dimensional space.
See what is E8? Those vectors are the vertices (corners) of an eight-dimensional object called the Gosset polytope 421. In the 1960s, Peter McMullen drew (by hand) a 2-dimensional representation of the Gosset polytope 421. The image shown below was computer-generated by John Stembridge, based on McMullen's drawing. AIM math: Representations of E8.