Hinge crease — where it appears
Named by 3 essays across one field — each of them below, with the objects they name alongside it.
Also named here as ridge crease — the same set of essays touches all of them, so they are one junction rather than several.
Every flap on one axis
The tree method does not design a shape. It designs a base whose flaps all lie along a single line — and that restriction, which is almost never stated aloud, is what makes the circle argument true.
From a packing to a crease pattern
The circles say where the flaps are. They do not say where to fold, and the step in between is a construction rather than a search — two families of crease, both determined by the packing, neither of them visible in the picture of the discs.
Two packings, one radius
A packing search reports a number, and the number is not the design. What a crease pattern is built from is the graph of which discs touch which — and at five and six flaps, runs of the same search that agree about the best radius to four decimal places come back with contact graphs that are provably not the same graph. The answer an optimiser gives has not determined the pattern it is supposed to have found.
Named alongside it
The objects these essays reach for when they reach for this one.
Ridge creaseUniaxial baseCircle packingAxial polygonContact graphDesign hypothesisOptimisationProjectionTree method