“In Euclid's Elements we meet the concept which later plays a significant role in the development of science. The concept is called the "division of a line in extreme and mean ratio" (DEMR). ...the concept occurs in two forms. The… — Alexey Stakhov Copy Share Image
“Much as Euclid proved that there can only ever be five 3d Platonic solids, over two millennia later Schafli proved that there are definitely only six Platonic solids in 4D.” — Matt Parker Copy Share Image
