Made of left over cinder from Dow Chemical's coal-burning furnaces, the unit block became an important material in Alden Dow's career. He arranged the rhomboid blocks to as to appear square in the Dow house, and painted them a bright white. Photo 4 of 30 in Michigan: Day One by Aaron Britt

Michigan: Day One

4 of 30

Made of left over cinder from Dow Chemical's coal-burning furnaces, the unit block became an important material in Alden Dow's career. He arranged the rhomboid blocks to as to appear square in the Dow house, and painted them a bright white.