I couldn’t help holding my breath as Roy poked the toe of his trainer under the log and levered it out of the grass. It wobbled on two of its stumps and then came down on all of them. Either the impact stirred the grass around it or the departure of unseen insects did. When the activity subsided I couldn’t quite see where it stopped, perhaps because I was distracted by the appearance of the log, crouching on all fours to thrust forward its round slab of a face. It might have been a carving of a guardian of the woods, blindly alert for intruders and poised to leap. “She should have put that in a picture,” Roy said.

He was already striding onwards, and I made the effort to outdistance him, which gave me an excuse to glance back. Had the grinning log toppled over? At that distance I couldn’t be sure, and the long grass didn’t help, but I thought the stumps resembling a caterpillar’s legs might be uppermost again, as though it had twisted onto its back to await the next visitor. While this was a notion my aunt might have had, I was happy to leave it behind.

Ahead the path split into a pair that appeared to be marked as green as the leaves that shaded them. I took the left-hand route, which was slightly more gravelled than its equally overgrown neighbour. My instincts suggested that it would eventually bring us back to the car park. It led through a tunnel of trees, beneath branches heavy with leaves. The foliage was so abundant that long before we reached the end I began to feel as though the laden boughs were about to nod towards us, lowering the leafy roof. The notion reminded me of a carnivorous plant, and I was glad to emerge into relatively unobstructed sunlight, even when I saw a pattern of stones beside the path. “What are you thinking now, dad?” Roy said.

The sight had made me falter. The four grey stones were bare except for a fur of lichen, which didn’t lessen their resemblance to inverted hoofs. “My aunt showed me something like that in here,” I admitted. “Someone’s buried a horse upside down, she said.”

“That’s kind of what they look like,” Roy said and scrutinised my face. “She said more stuff, right?”

“She told me there were places where the world could turn upside down or inside out. Supposedly her friend told her.”

“Which friend?”

“I think it may have been the man she left my uncle for.”

Roy’s interest flagged or at any rate reverted to the sight beside the path. “Did she show you how turning things round worked?”

“There’s her painting where all the trees you think are convex are concave, and all the spaces between them are inverted trees.”