Oddbean new post about login | logout International Fixed Calendar was used by Kodak… “By 1928, Kodak had implemented Costworth's calendar and Eastman himself took on the responsibility of promoting it to the world on his dime.” “Favored by leaders in transportation and logistics, the International Fixed Calendar was a favorite of Kodak founder George Eastman, whose company used it until 1989.” https://en.m.wikipedia.org/wiki/Metonic_cycle