Dissection of Two Squares into Three Squares
This Demonstration dissects two squares into three squares, two of which are congruent. This dissection is based on the formula , where is the golden ratio.
For more on square dissections see [1, pp. 65–69].
 G. N. Frederickson, Piano-Hinged Dissections: Time to Fold!, Wellesley, MA: A. K. Peters, 2006.