sentences:  It was recognized as a National Historic Landmark on June 29, 1989.Begun in 1937 and expanded over 25 years, this is the first and best example of Wright's innovative hexagonal design.A Usonian home patterned after the honeycomb of a bee, the 3,570 square foot house incorporates six-sided figures with 120-degree angles in its plan, in its numerous tiled terraces, and even in built-in furnishings.