<?xml version="1.0" encoding="utf-8"?>
<!-- Geometry Snacks #36 (Prove it!), drawn by hand as a ruler-and-compass construction.
     The triangle ABC stands on the hidden points A and C; the handle B, its apex, moves inside a hidden rectangle above
     AC that keeps B farther than half of AC from both A and C, which is what the shape needs. The width is d = AB + BC,
     as the book's figure has it: then the small arc about B has the radius AC/2 (Mb is the midpoint of AC), the small
     arc about A the radius BC - AC/2 and the small arc about C the radius AB - AC/2; each big arc has the width less
     the small arc's radius at its vertex. The six ends of the arcs are where the circles of those radii about A, B
     and C meet the lines of the sides beyond the vertices (P and P' are the points at AC/2 from B on BC and BA, whose
     distances to C and A are the other two small radii). The dashed segments run from each vertex to the ends of the
     arcs on its two sides; the six arcs are centred at the vertices, each between the two ends on its lines. The dots
     at A and C are where the lines of the sides meet, so that the letters have a shown point to hang on. -->
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