The first six books of the elements of Euclid, in which coloured diagrams and symbols are used instead of letters for the greater ease of learners (1847)
Byrne, Oliver, Whittingham, Charles, 1795-1876, Chiswick Press · London : William Pickering · leaf 279
Q ED 246 BOOK VL PROP. XXI. THEOR. … ECTILINEAR Jigures (
Euclid's Elements · Geometry
Internet Archive · Getty Research Institute · Public Domain Mark 1.0. Free to use for anything.
