This steel framing square, one of a set of three, is L-shaped and flexible, with markings in green. It is used for conversion from shaku (a traditional Japanese unit of measurement) to the metric system. The framing square was used by carpenters during the construction of The Japanese House in 1979. Squares were used to lay out all joints (no tape measures or levels were used); the squares are very flexible and can get "out of square"—that is, they need to be calibrated, which is done by hammering.