The LEGO Group is a Danish company started in 1932. It expanded to producing plastic toys in 1947. In 1949 Lego began producing the now famous interlocking bricks, calling them "Automatic Binding Bricks". These bricks were based largely on the patent of Kiddicraft Self-Locking Bricks, which were released in the United Kingdom in 1947. Lego modified the design of the Kiddicraft brick after examining a sample given to it by the British supplier of an injection-molding machine that the company had purchased. The bricks, originally manufactured from cellulose acetate, were a development of traditional stackable wooden blocks that locked together by means of several round studs on top and a hollow rectangular bottom. The modern Lego brick was patented on 28 January 1958; bricks from that year are still compatible with current bricks. The company has produced animals as parts of many of it's building series.