Watch the earth as it turns on it's axis...
A circular area has a shallow pool of water at itís centre. A canopy covers half the area and is open to the south. Seats around the circumference are invitations to stay. Sunlight reflects off the surface of the water to produce a perfect ellipse of light in the shadow of the canopy.
The reflection slowly moves as the earth turns, sparkling as wind or rain ripple the surface of the water, responding to passing clouds and the changing quality of light during the day.
This smaller version is animated to demonstrate the effect through the day.