Six books · 173 propositions · rarity by Euclid
The books are the traits.
Triangles & parallels
Equilateral constructions with their compass arcs, congruent pairs, coloured angle sectors — and the windmill of Proposition 47, the most famous diagram in mathematics.
Squares & gnomons
Geometric algebra: dissected squares, complements, L-shaped gnomons under a drawn diagonal. Mondrian, seventy years early. The fourteen canon plates of the pilot book live here.
Circles
Inscribed angles, chords and their segments, tangent lines at their point of contact, circles touching circles, rings within rings.
Figures in circles
Triangles, squares, pentagons, hexagons and the fifteen-sided figure, inscribed and circumscribed — fans, rings, and alternating segments.
Proportion
Byrne's most abstract pages — magnitudes as rows of coloured units, squares, circles and diamonds in ratio. Minimal art, 1847.
Similar figures
Nested similar triangles, the mean proportional beneath its semicircle, and the golden section — extreme and mean ratio, with its spiral of dashed arcs.
