Abstract

We construct an explicit one-parameter family of embedded spacelike polyhedral slices of a fixed spinless conical spacetime with deficit $\mu =\pi /2$. The family agrees with a prescribed resting exterior and has exactly one incidence event: the link of the particle changes from three incident faces to six. Six vertices, twelve edges, and six faces are born at the particle; their coordinates, lengths, areas, and one-sided laws are given exactly. A finite table of adapted affine charts yields identity products around regular vertices and the full spinless conical identification around a primitive meridian. The incoming germ, outgoing germ, and annular collar have the same framed affine peripheral holonomy. For an explicitly stated geometry-only interface, the event has spectator-blind control, a forward-domain decoder, and an exact NOT–CNOT–Toffoli implementation with separately reserved location and history storage. The result is a kinematic consistency certificate for one prescribed slicing event.