O great computer! (Venus)

Weeks passed, and once he had overcome the initial shock of his parents' announcement, Rhys was able to work once again on the grand plans under his bed and in his head. With time no longer on his side he decided to take a notebook with him to the site and back. It increased the risk of his discovery, but was necessary to speed up his studies during the month or two—perhaps even less—remaining to him.

He made several experiments based on his earlier observations. A position near the twenty-fifth Aubrey hole provided some solace, but only if he did not turn round: rotational movement gave him away. He found he could pass along the permitted sections of a route curving between the Station Stones to touch the edge of the South Barrow, and be utterly unnoticed as long as he kept moving. He repeatedly walked sections of this route, in between tourists and their cameras, or their cameras and the stones, but they all seemed oblivious to his passing (he wondered if they would even spot him when they looked through the photographs later). But when he stopped suddenly during a particular transit, made wary by an approaching official, he saw the looks on the faces of people nearby suddenly change: their eyes flicked towards him, and some of them even turned to gape at this young man suddenly in their midst. That route was not perfect, he realised, but it provided clues to perfection.

Before long his mind was a heap of geometry, shapes and paths lying round like fragments of pottery with thin straws between them. One day, with driving rain trapping him in the house, Rhys sat at his desk and stared out at the weather, willing it to improve so that he might return to his fieldwork. Then, suddenly, it was like a flashbulb had ignited in his brain, but a moment afterwards burnt out and disappeared.

That's it, Rhys thought. That's the place I'm after. I had it just now, but I lost it again.

He screwed up his eyes to concentrate, to try to sift out all the chippings and clutter that hid the genuine artefact, the shards that did not make up his prize. Like an archaeologist he peeled and lifted, and then brushed away the dirt from whatever was left. He stoppered his ears to the rushing, pattering sound of water falling outside and pictured instead the stones falling from the sky.

He saw the site, empty of its building work, the midsummer sun making the green grass lush and wet. Into this pastoral scene dropped rock after rock in slow motion, each shuddering and grinding to a halt as the others followed closely behind. Gradually, they built themselves up into an irregular pile, tumbling down and striking each other, crashing together and bellowing a clattering lament across his brain.

Finally, with one last thump, the disorder he saw contained every stone that ever was placed, and some that never were, ones that Rhys himself would himself have placed given the chance. All the stones necessary for the perfect henge were there, the henge that would have made its purpose obvious to anyone.

Then, as Rhys put his fists to his temples, the sun itself detached from the imaginary scene, and floated down into the centre of the mound, shrinking and brightening as it did so. At its touch, the stones rolled away, scuttling into position. One by one they put themselves in their correct locations as their builders had intended, leaving the now blinding point of light where Rhys now knew he would have to reach: there, precisely there, he could be unseen by and unseeing of everyone else in the world. Everyone else would disappear, and he would too.

Rhys opened his eyes at this realisation, and saw his goal clearly. To reach it was the puzzle now. There was no perfectly invisible route, he knew. But what was important was that, en route, nobody was to see him: he could accept, briefly, seeing others. And if he were visible in theory to the rather sparse crowds milling around, he could content himself on the journey with being effectively out of sight, with people hidden temporarily behind those merely physical artefacts, the stones themselves.

It was necessary to return to the plan. He closed his eyes again, and the completed structure was once again presented to him, a bright globe marking the point of perfect balance. Remembering each aspect of his workings and jottings in turn, he overlaid the networks he had discovered on top of the henge, the networks that the henge itself mapped out in secret.

He twisted and pulled at each of the lines between points, one by one; they barely yielded, but clicked instead from one archaeological socket to the next, like dislocating joints: 31st hole to Northern Low; Heel to the Great; blue to blue. He shifted his axes, pushed again, bent the spokes between Y holes and Z holes, brought his weight to bear on the path from the Avenue, and then, without any warning: joy!

He had almost everything he needed: the why, the where, and the how. Now he only had to wait for the when.