A diffraction pool

I found an interesting pool when I was strolling along English Bay. There were piles of rocks partly along the beach to protect it from wave's erosion, and at one place, there was a small slit. I don't know whether it was artificial or not, but it was leaking sea water into the beach shaping a small, semicircular pool like this picture. The waves inside the pool looked like a diffraction stripes. I think it is a miniature of the Gulf Islands where we sailed last week. Of course the rocks correspond to Galiano, Valdes and Gabriola Islands, and the slit does to Active, Porlie and Gabriola Passages. It's interesting that the Nature works just under the same law whether it is about a small gravel or a gigantic mountain or island.