american robert gair was a brooklyn printer and paper-bag maker during the 1870s, and while he was printing an order of seed bags a metal ruler normally used to crease bags shifted in position and cut the bag. gair discovered that by cutting and creasing cardboard in one operation he could make prefabricated cartons. extending this to corrugated cardboard was a straightforward development when the material became available. by the start of the 20th century, corrugated cardboard boxes began replacing the custom-made wooden crates and boxes previously used for trade.