Well, Kate said I would talk about the coaster designs, so here goes!
The first one (upper left) is a design I came up with while drawing a replica of one of pages from the stunning Lindisfarne Gospels. (See the page I was copying here.) I was drawing this part--
--and then I noticed that if I changed the angle a bit I could turn it into a design with a continuous pattern. Voila!
The next one (below) is not a design I can really claim as my own. It's just four trinity knots put together and I bet someone, somewhere has done that before!
The last design is very simple, really. It's just four overlapping circles. But when you create each circle with two parallel lines and follow the ancient tradition of going either over or under whenever you encounter another line, and the next time going the opposite, it can make things appear fairly intricate. Which, of course, is more fun for us!
And there you have it!