The Foreshortened Square.
Circular shapes are not the only ones that are foreshortened when they are seen under certain conditions. Figure 1 on this page is a picture of a square hat-box, showing the top and two sides. Not one of the three shapes is seen as it would actually measure. The top looks like a long narrow diamond. It is not so different from the shape of a narrow ellipse as you might at first suppose. If you changed the straight lines into curved lines, rounding off the four corners or angles of the diamond, you would have an ellipse. You could also place a box like this turned cornerwise, so that its top would look like a straight line. Where would the top be to look like that?
The two sides of the box are also foreshortened in this position; they appear shorter from front to back than they really are. You can see that the two farther vertical edges or corners appear shorter than the nearer one, just as trees in the distance appear smaller than trees of equal size near you. The lines on the top and bottom of the box appear to slant upward, instead of keeping their actual direction, which is horizontal.
Figure 2 shows the same box with the cover off. The inside was lined with colored paper and the dark value of the diamond-shaped mass adds interest to the picture.
Place cornerwise, on a table in front of you, a large box with a square top. See if the three faces in sight are foreshortened. Notice if the edges appear changed, in direction and in length. Make a sketch in outline, showing just how the box appears to you.
Measuring a Foreshortened Surface.