At the age of 19, Gauss was the first person to accomplish the ruler and compass construction of a 17-gon polygon. This proof represented the first progress in regular polygon construction in over 2000 years. While doing it, he also discovered this expression for cos(2π/17) pic.twitter.com/AByfnuMDcr
— Fermat's Library (@fermatslibrary) February 19, 2020