Coiled snake silhouette design

The snake came back again this morning, right across the threshold of the old postern where the cart track gives out. I had the trowel in my hand and was halfway through pointing the north wall, and there it was, lying in the sun on the cold flags as if it had been sent for. Black as wet slate, head lifted, tongue flicking at me like it was reading my handwriting. I said good morning. It did not answer, which Mrs Pryce would tell you is the proper manners of a snake.

Mrs Pryce at the farm says it's the castle's old keeper, come back to watch the gate, and she says it the way she says the price of eggs. I don't believe her, but I've stopped sneering at her. Last week the lads from the village wanted to chase it into the moat with sticks, and I stood in the gateway with my arms out and told them the place had outlasted three sieges and a Cromwell, so it could manage one snake. They laughed, but they went home.

Here is the odd part. Yesterday I measured the coil it makes when it sleeps, and it is exactly the bend of the arch above the portcullis, the one the masons cut in 1340 and nobody has looked at properly since. I have drawn it for you on the back of this sheet. Hold it up to the window and you'll see.

The foreman wants the postern boarded up by Friday, but I've asked him for one more week. Come up in the spring and bring your drawing kit. I want you to draw the snake properly before the scaffolding comes down, so it's kept somewhere besides my head.

Your loving sister, Nell