Pie & donut in 1801: Encoding

Playfair 1801; Florence Nightingale’s coxcomb is a polar cousin, 1858 Yes if one claim is visible at a glance in Meta, Google and retail print; otherwise link to a full figure. Yes for lab reports and poster boards if axes, units and a source line are present. Excel or Google Sheets or PowerPoint; export SVG/PDF.

Do not rely on hue alone. Label directly and check greyscale. Pie & donut: honour angle (and area) of a circle slice, and switch when many similar slices, 3-D pie, or comparing two pies. The core mark of Pie & donut is angle (and area) of a circle slice. two to five parts that sum to a meaningful whole

The eye compares length and position more accurately than area. PowerPoint, Excel or Google Sheets and Meta, Google and retail print share the same geometry. Decoration rarely persuades; it slows reading. Perspective distortion wrecks comparison. Keep it flat. Do not stack stories. One Pie & donut, one claim.