Sunday night, I came to the following passage in Jeanette Winterson's Written on the Body:
"The interesting thing about a knot is its formal complexity. Even the simplest pedigree knot, the trefoil, with its three roughly symmetrical lobes, has mathematical as well as artistic beauty. For the religious, King Solomon's knot is said to embody the essence of all knowledge. For carpet makers and cloth weavers all over the world, the challenge of the knot lies in the rules of its surprises. Knots can change but they must be well-behaved. An informal knot is a messy knot."
That's two more references to trefoil knots than I usually get over the course of a weekend.
Speaking of Written on the Body: I know the point is that the gender of the narrator isn't specified, but I'd be astonished if that guy isn't a guy.