There was a figure who stood at the place where two paths divided and could not choose between them. This is said to be the beginning of the shimmer, though the word came later. The figure had no name that is remembered. Only the standing.
They stood for what the story calls a long time. Long enough that the grass where they stood flattened and then grew back and then flattened again. Long enough that the season changed.
The paths were equal. This was the condition: both led somewhere reasonable, and the figure knew this, and knowing it made choosing impossible. To choose one was to abandon the other, and both abandonments felt wrong in the same way, and so the figure stood.
But standing is not still. Standing is a continuous act of small corrections, a constant negotiation with gravity. The figure stood and their body compensated and adjusted, and over time the compensation accumulated in one direction. They began to tilt. Not toward one path or the other, but forward, the way anything tilts when it has been upright too long in one place.
The tilt was not a decision. The tilt was just what happens when weight has been held slightly wrong for too long. And the tilt became a lean, and the lean became a movement, and the movement was a foot lifting from the ground, and then the foot came down.
On which path it came down, the story does not say, because the story is not about that. The story is about the foot lifting.
After the foot came down, the figure walked on. Whether they had chosen, or simply fallen forward in a direction, no one later could say. They walked until they could not see the crossroads anymore, and then they walked further, and eventually the question of whether it had been a choice became something that only other people asked.
But the place where they had stood for so long stayed flat. The grass came back slowly. For a season or two you could still see the shape of where someone had stood for a long time.