rectify-a-plane
reflection-is-a-second-camera
reversal-against-distance
rolling-rows
row-two-ways
sag-against-depth
sag-against-offset
scale-across-the-field
scale-is-not-recoverable
screen-chain
seen-from-the-wrong-distance
seven-flat-directions
shadow-length-curve
shape-recovered-size-not
shift-keeps-verticals
shift-or-tilt
size-against-distance
snells-window
spheres-across-the-frame
splay-is-a-tilt
stitch-error-against-distance
straight-family
straightened-in-place
stretch-and-its-cure
stretch-at-the-station-point
sun-shadows-converge
surface-panels
the-adjustment-converges
the-baseline-in-the-spectrum
the-best-single-direction
the-centre-that-is-not-there
the-chain-wanders
the-cone-rule-is-about-the-reader
the-image-of-the-other-eye
the-lamp-as-an-eye
the-last-tenth-of-the-page
the-matrix-is-the-camera
the-plane-that-leans
the-ramp-and-its-horizon
the-range-a-pair-cannot-see-past
the-ray-that-bends
the-relief-family
the-scale-identity
the-strip-a-wall-hides
the-track-and-the-scene