A book you might want to look up:
Sandburg, Carl. Arithmetic. New York: Harcourt, Brace, Javanovich, 1993.
ISBN 0-15-203865-5.
Ted Rand has illustrated Carl Sandburg's poem for children, Arithmetic, as
an anamorphic adventure. Anamorphic art is a term used to refer to a
picture that has been compressed or stretched so that it appears distorted
until it is viewed in a particular manner. The images in Arithmetic can be
seen normally by viewing them from an indicated angle or by viewing their
reflection in a cylinder.