This is sunlight reflecting off a metal pail onto the cement ground which is in shadow. The pail's surface is not perfectly smooth and has become even less so with use over the years so the reflection produces this lovely abstract pattern from all the slight dents and imperfections on its curved surface.
This pattern is only visible when the reflection lands in shadow - elsewhere the sunlight is too strong. And it forms a lovely arc around the pail, which is then reflected back onto the metal surface for a kind of double reflection!
When I first noticed it the coincidence of the sunlight hitting the pail but the reflection landing in shadow was fortunate. But after noticing, it was easy to move the pail around to try to get the best reflection I could.
Two pails together also work well.
And finally a detail of the reflection by itself. A lovely abstract, almost watery, unintentional design.
