Lunulae

Every spot of light under a tree is a picture of the sun.

Shaded ground seen from above, under a swaying canopy. Every gap in the leaves is a pinhole, and a pinhole throws an image of the sun whatever its own shape, so every spot on the ground is the same size; the gap only decides how bright and how soft it is. The sun itself is never in the frame.

Once a loop the moon crosses the sun. Every spot takes the same bite at the same instant, whatever its size or position, and by the middle of the loop the ground is a field of thin crescents. They point the opposite way to the eclipse in the sky, because a pinhole turns its image over. Then the moon moves on and the spots fill back to round.

The moon crosses at constant speed, as a real transit does, and leaves the disc before the loop closes, so the seam is invisible. The exposure opens partly as the sun dims, the way an eye adapts, and the ground still darkens.

Rendered offline from a single closed-form shader by the same module code a live page would run. No camera, and nothing leaves the machine.