People live beside an ancient wall. In the wall is an aperture, a window, which has great cultural significance for them. Many of them gather regularly to stare at the window, an odd practice, as all the panes are opaque; you can see nothing through it, though it does, to a very slight degree, admit light, at certain times.

These are the times when the people most like to gather at the window, because it glows dimly in a mysterious way which they find profoundly moving – they tell themselves and each other that this is why the window is revered as the foundation of their culture.

A strong tradition has grown up of drawing life-lessons from the window in the form of stories or sayings; they are the sort of thing the people take comfort from when they are troubled or perplexed or grieved.

The window itself is sacred: you have to be specially ordained to be allowed to touch it, and even then it must be done with the utmost reverence – this applies particularly to the glass panes. The frame, which is said ‘once upon a time’ to have been very plain, has over the years, as an expression of people’s piety and reverence, become increasingly ornate, decorated with carvings and gilded with real gold leaf.

(This practice occasionally causes friction among the faithful, and from time to time a puritan party holds sway, and they insist on getting everything back to its original unadorned plainness, though this only lasts for a time before it begins to accrete new ornament)

One night, when no-one is around, a young child rubs one of the sacred panes with a wet finger and creates a streak in the age-old layers of dirt. Through the streak he glimpses a sliver of light. Fascinated, he carries on till every pane is clear as crystal and he sees through them against a background of velvet darkness the slender crescent of the moon and a myriad stars.

He gazes in wonder till he feels sleepy and goes off to his bed.

Next morning, the people gather and gaze through the window in utter astonishment at the sun rising on a beautiful landscape. Their understanding of the window and their culture is transformed.