Learning and geometry

Slope notation (sun, bu, fractions, percent, per mille, degrees)

Slope notation: roofs in sun, ramps in fractions, roads in percent, railways in per mille — degrees are the minority

This drawing comes from one YAML file. No shape was moved by hand.

Notes in the source (in Japanese)

Source (YAML)

examples/gallery/196-勾配の書き方.zumen.yaml

More in this field

• Ray tracing through a convex lens: there are only three lines to draw, and two of them fix the image
• A football is a truncated icosahedron: the 12 degrees missing at every vertex are what make it a sphere
• Braille has only six dots, so “a” and “1” are the same shape until a number sign says otherwise
• Isometric, third-angle and oblique: one scale serves all three axes, but circles become ellipses
• Honeycomb cells: for a given area the hexagon has the shortest wall of any shape that tiles
• Ruler-and-compass constructions: no scale is used, because equal compass openings make equal lengths
• Figures in maths problems: the marks carry the meaning — equal ticks, right-angle squares, parallel chevrons — and only the given values are written on the figure
• Two set squares come as a pair because two of them make ten angles in 15-degree steps, where one alone makes only four