Meniscus

Always wanted to use that word. If you haven't figured out what this is (and you have a few seconds), you might reflect on it for a moment. It reminds me of some of the wall-hangings Le Broquay made (or had made) based on his Táin illustrations. This would be a kind of Op Art version of them. Not the kind of photo I usually take but it jumped at me when I saw it.

If you can't figure it out, THIS LINK will tell you what you need to know.