c. The center of the circle shifts from the center of the square when
the circle is in perspective.
The intersection of the diagonals is the
perspective center; the intersections of the horizontal centerline with the
lines drawn back to the vanishing point does not indicate the widest part of
the circle in perspective.
d. When drawing circles in perspective, it is often best to rough them
in freehand and get the general shape desired.
When the square is
proportion ally correct, cross the center with two diagonal lines and cross
these with a vertical line through the intersection of the diagonal lines.
Draw a horizontal line through the center to determine the perspective
center. Use the vanishing point to have the direction of the receding lines