Inspired by the Pier Cluster Windows design in the Frank Lloyd Wright Darwin D. Martin House. Constructed of coir fiber pressed into a rubber base. Dimensions: 30 inches x 18 inches. Official Frank Lloyd Wright Collection item. The Frank Lloyd Wright Darwin D. Martin House Welcome Mat Doormat is inspired by the Pier Cluster Windows design in Wright’s Darwin D. Martin House. This doormat is constructed in coir fiber pressed into a rubber base. The generous proportions of this mat are 30 inches by 18 inches. Officially licensed by the Frank Lloyd Wright Foundation.