The voussoirs are wedge-stones. Each has a number painted or charcoal-cut: 1 at the spring, climbing toward the crown where the keystone will sit like a last word.

You walk the rib with a board. 1, 2, 3… 7 looks like 9 in a hurry. Or 12 has been set where 11 should wait. A swapped stone is a polite lie. The curve will go almost right, then not, and everyone will blame weather or saints or apprentices.

Ned swears without swearing: a long carpenter breath.

“We correct on the centering or we correct in a year with a crack.”

Wind increases. Lamps will be needed. Rowan may be at the gate with a wrapped crown.

Numbers hide on the bed-face. You need to kneel. 7 that looks like 9 is a charcoal crime. Swapping back now is a nuisance. Swapping later is a crack that will be called mysterious, then expensive. Ned would rather a nuisance.