Dotwork moth in sacred geometry

The lamps at the post have drawn the moths again, so many that the tarmac looks like it is breathing. Last night a large one, the grey of old cathedral stone, settled on the glass of my booth and would not leave. Sergeant Holm said to flick it off with the ledger. I did not.

I have started keeping a record of what crosses in the dark. Lorries with their papers in order, a priest who coughs through his whole passport, a girl who carried a cage of canaries and swore they were for her grandmother. The moth crossed nothing. It only walked the length of the barrier, paused on the painted eye above the gate that the council put there to remind drivers of the speed limit, then climbed the diagonal of the wooden arm where the blue paint has worn down to the grain.

On the third night I drew it. You know I cannot draw, but I copied the pattern from its wings onto the back of a customs form: dots, always dots, thousands of them, each one a small decision about how dark a thing must be before it becomes a shadow. Holm laughed and said I had made a map. Perhaps I had. Dark where the wings are heavy, pale where the moon sits on them like a thumbprint.

This morning the moth was gone and the crescent moon hung low over the hills, thin as a fingernail. I stamped the day's last form, APPROVED, and found a single grey scale on the desk beside it. I have pressed it into the ledger at the page for the night you left. Come home when the lamps are off. I will wave you through myself.

Your sister, Irena