The Elements of Perspective / arranged for the use of schools and intended to be read in connection with the first three books of Euclid

by John Ruskin

a d

beneath it.

Within the square E F G H describe a square I K, whose diameter shall be equal to

a b

.

Describe a circle within the square I K. Therefore the circle so inscribed has its diameter equal to

a b

; and it is [p88] ]in the center of the square E F G H, which is vertically beneath the square A B C D.

Therefore the circle in the square I K represents the bottom of the dish.

Now the two circles thus drawn will either intersect one another, or they will not.