This pattern of wrinkled humps of seaweed on the rising tide is relatively unusual. It takes several different weather and tide conditions conspiring together to create it.
It goes something like this: First, a southeast wind must blow at low enough tide to accumulate a build up of copious amounts of sea lettuce on the beach. Then, the further receding tide must distribute that sea lettuce over a large patch of the shallow sloping sand, a few inches thick. Then, day must be hot enough to dry the surface of the sea lettuce while the tide has ebbed. The third requirement is that the wind drop, allowing a calm windless period while the tide rises. The result is that the thick layer of sea lettuce is moved slowly from beneath, while the baked-dry surface of the sea lettuce layer is more resistant to movement, and makes for these extraordinary folds.
To me it looks something like colourful elephant skin. Or perhaps a satellite photo of mountain ridges. Or the flowing of some strange green river flowing from the distant rocks… What do you think??