In this panel I've created, the knot in the center (which would date to about 600 to 700 AD and can be seen in examples like the Book of Kells) is paired with an earlier style of Celtic art called the La Tene style. The La Tene period in Celtic history dates from approximately 450 BC to 50 BC, and is names for the La Tene valley in Switzerland, where a large amount of early Celtic artifacts were found. These artifacts were patterned all in a similar style, and since then this style of artwork from this period is usually called the La Tene style of Celtic art. It's a very loose and organic style of art, characteristically full of tendril and loops, rather like plant life.