Design that I stumble upon while googling for knotwork images in 2010. Found first on [this site](https://web.archive.org/web/20100906221903/http://www.mythicalmatters.com:80/All%20Celtic%20Art.html) but it seems to be actually an original creation from https://www.touchstonepottery.net/celtic-art-product/knotwork-octagon that can be seen also on various resellers' websites.
Redrawn back then in Blender using 3d curves.