(2) If the square is distorted, as shown in (B) (figure 11 on the

previous page), the diagonals are no longer the same length; Y is no longer

than X.

(3) If this figure frame (B) is visualized with movable corners, it can

be seen where pressure must be applied to make it square; at the corners of

the Y diagonal.

(4) The original length of either the sides or diagonals need not be

known. By making comparative measurements of the diagonals, it will be

shown that when they are again equal, the frame is again perfect as it was

in (A).

(5) In (C), it is possible for the diagonals to be the same if the

distortion is exactly at the mid point of side (A). Therefore, by a

comparison of sides, (A) can be straightened until both side (C) and side

(A) are the same length. These illustrations show how it is possible to

align a body or frame by measuring the body or frame alone.

FIGURE 12. DIAGONALS OF CUBES ARE

ALWAYS OF EQUAL LENGTH.