Nicht-Euklidische Geometrie
Felix Klein's lecture notes on non-Euclidean geometry, issued at Göttingen in 1893 as a hand-lettered autograph reproduction for university mathematics students. The figures are pen diagrams of conics, tangent lines, and coordinate triangles, with shaded regions built from parallel hatching and German script captions beside numbered points, useful for line-weight studies, hatch textures, and handwritten annotation on plain cream ground.
