Gr?nbaum and Shepard wrote about the problem in their 1987 book Tilings and Patterns [4]. They described there a second way in which a squared square S can generate a tiling of the plane (in addition to the method indicated in the present paper): Take a second copy of S and expand it to a square S such that the smallest square in S is the size of the original square S and fit S into that square. Take another copy of S and expand it to S2 so that its smallest square is the size of S, and so on. Gr?nbaum and Shepard record the observation of Carl Pomerance that in every tiling of the plane by unique squares known at that time, the sides of the squares grow exponentially.