About 1950, Frank Lloyd Wright designed a concrete masonry building system that he called Usonian Automatic. Automatic was used to suggest that the owner might participate in the actual construction of the home, laying or even making the blocks. Beginning in 1951 a number of these houses were constructed across the nation from California to New Hampshire.
The basic concrete block of the Usonian Automatic system is 4x12x24 inches. The blocks are laid up without mortar, with #3 reinforcing bars placed both horizontally and vertically in semicircular voids in the contacting faces. After one or two courses of blocks are laid, grout is pumped or poured into the voids to embed the bars and bond the structure together.