The floor is tiled.
The floor tiles are perfect squares.
Not all tiles are perfect squares.
exists e1 x1.(n_floor(x1) & Theme(e1,x1) & v_tile(e1))
exists p1 x1 x2.(n_tile(x1) & of(x1,x2) & n_floor(x2) & exists s1 x3.((x1 = x3) & n_square(x3) & a_perfect(s1) & Theme(s1,x3)))