For Patty and others, who’d like to follow the action more closely…

This diagram, which figures so prominently in The Bellini Card, is an eight-pointed star inside a square. The above illustration comes from a Japanese website and it is, as far as  know, the only illustration of the Sand-Reckoner’s diagram online.

The idea that it was used as a fencing diagram, governing positions and strokes, was put to me in Hampshire some years ago. It has been on my mind ever since, not least because of its delightful name:  I was glad to unpack it for The BelliniCard.