The first rubber ice cube tray was made by Lloyd Groff Copeman. One day in 1928, while walking through some woods getting sap for maple syrup, Copeman saw that slush and ice came off of his rubber boots instead of sticking to them. After talking about it with his patent attorney at lunch, he did experiments using rubber cups. Later, he made and patented several kinds of tray: a metal tray with rubber separators, a metal tray with individual rubber cups, and a tray made of only rubber.