Cross ratio test — where it appears
Also named here as necessary, not sufficient — the same set of essays touches all of them, so they are one junction rather than several.
Dividing depth by eye
Three methods for spacing a receding row, all of them taught, all of them wrong. Read back as distances, the best misplaces a post by 3.5 metres in a row that is supposed to be spaced 1.4. And the obvious way of checking them gives one of the three a perfect score.
Each system answers its own question
A comparison in which every system wins its own column proves nothing if the columns were chosen after the systems. The test that makes it a result is whether any system wins something it was not designed for — and two of them do.
Named alongside it
The objects these essays reach for when they reach for this one.
necessary, not sufficientAxis scaleConformalDemonstrationDepth divisionDiminutionDrawing systemFree parameterHorizoninstrument limitInverse projectionMeasuring point