Knots Celtic Pattern KnotCourtesy Needpix.com Mayan Symbol Aztec Ancient Mexico Celtic Tribal Knot Celtic Tribal KnotCourtesy Needpix.com Terracotta Humbaba mask from Ur, Iraq. 2004–1595 BCE. Sulaymaniyah Museum, Iraq More complex form of the endless knot seen on a c. 400-year-old Chinese lacquerware dish Decorative form of the Tibetan endless knot Tibetan endless knot.