Torsion

Two rigid jaws hold one ruled plate and turn it against itself. The section is cut away at a single off center station, so the turn crowds there and its fan collapses to one warm point. Outside, a strip starts on that same station and runs a member width and a quarter, one tick per rib, warm where the ribs across from it are warm. One white ordinate, square to both, ties its first reading back to the fixture.