The 1880 US patent for Anchor Stones states "the object is to produce toy building blocks which will always retain their shape and color, will not be dangerous to children, and will, by reason of their weight, better retain their position than if made of wood as usual." The result became Richter's Anchor Stone Building Sets (Richter's Anker-Steinbaukasten.) Stability, durability and natural all combine to make Anchor Stone building blocks the best blocks for children. But, you don't have to let the children have all the fun, because these blocks are also great for adults!