Click images to enlarge.
top: A knot in the style of knots from Irish Celtic illuminated manuscripts like the Book of Kells or the Lindisfarne Gospels, generated by the program (free to download, but donations gratefully accepted) KnotPlot, a program to manipulate the objects of the branch of mathematics/topology called Knot Theory.
bottom: Incipit (beginning) of Gospel of Matthew from the Lindisfarne Gospels, circa 700 A.D., attributed to Eadfrith, Bishop of Lindisfarne (Northumberland, England).
WARNING: Knot Theory (like Number Theory) can be so hypnotically beautiful that some people vanish into it and never emerge. That's okay with them, they don't want to be dragged back to our unexquisite reality.