The register

A tunnel driven uphill from the far end, dug in the dark from a line of vertical shafts, moving water tens of kilometres without a pump and losing almost none of it.

The domed cistern: stored water kept cold and still below ground, with wind-catchers drawing air across its surface.

An ice house that made ice in a desert, using a shaded pool, a thick tapering wall and radiative cooling on clear nights.

A qanat's flow was divided by time, not volume, and the schedule was law — which is why the ledger mattered as much as the tunnel.

Symmetrical against asymmetrical knotting, what each does to the pile, and why knot density is a poorer measure of quality than people assume.

Madder, indigo and the insect reds — where the colour came from, and how differently a natural dye ages against a synthetic one.

A field layout and a border can place a carpet by region and workshop; what the vocabulary actually encodes.

Village horizontal loom against town vertical loom, and what the difference does to the size and squareness of the finished piece.

The trade street: one craft to a run, so the noisy and the smelling sat apart from the fine work, and the whole thing was legible without a sign.

A domed hall off the main run, lit from above, where the higher-value trade sat behind one controllable entrance.

A courtyard building for animals below and people above, spaced along the routes at roughly a day's travel.

Brick vaulting with openings that vent hot air and drop light — a roof doing structure, shade and ventilation at once.

Strapwork built from a small set of repeating figures, laid out with compass and straightedge, generating patterns that never quite close.

Each colour fired separately then cut and set face-down into plaster — slower, sharper and far more expensive than painting the whole panel.

The haft rang tile: several colours fired together on one square, cheaper and faster, with the softer edges to prove it.

The stalactite vault as a system of stacked cells that turns a square room into a dome without anyone seeing the transition.

Two crossing channels quartering a walled rectangle — a plan that is a water distribution diagram before it is an aesthetic.

The building set where the axes cross or at the head of the long view, sited for through-draught as much as for the view.

Shade first, fruit second, flower last — a planting order that follows what the climate will actually support.

Narrow, shallow and lined to be heard as much as seen, with drops placed to make the water audible from the pavilion.

Mud brick as a structural material with real limits: enormous thermal mass, no tensile strength, and a maintenance cycle built into the design.

The wind-catcher as a pressure device — catching breeze on one face, dumping warm air out the other, and working even on a still day.

Decorative bonding that is also structural: the pattern is the coursing, not a surface applied afterwards.

How a round dome gets carried on a square room, and why the squinch preceded the pendentive here.