Apostol, Mnatsakanian: New Horizons in Geometry : https://www.amazon.com/Horizons-Geometry-Dolciani-Mathematic...
See also: https://en.wikipedia.org/wiki/Visual_calculus
Apostol, Mnatsakanian: New Horizons in Geometry : https://www.amazon.com/Horizons-Geometry-Dolciani-Mathematic...
See also: https://en.wikipedia.org/wiki/Visual_calculus