“On what may be the last page he wrote in his notebooks, Leonardo drew four right triangles with bases of differing lengths (fig. 143). Inside of each he fit a rectangle, and then he shaded the remaining areas of the… — Walter Isaacson Copy Share Image
“The Project Gutenberg EBook of The Notebooks of Leonardo Da Vinci, Complete by Leonardo Da Vinci (#3 in our series by Leonardo Da Vinci)” — Anonymous Copy Share Image
