Knots. Holy trefoils, math fans!. The Inca & the Quipus. The Inca used quipus --colored strings with carefully placed knots-- to keep records of their trade with each other and with other tribes. A quipus. Knots and Art. Celtic artwork uses knots. Knots and Sailing.
Holy trefoils, math fans!
Bowline Knot (pronounced Boh-Lin)