This is based on a key pattern from the Book of Kells, which was made by Celtic Monks in about Ad 800 and is considered the high point of Celtic art. The Celtic church didn’t really go in for buildings, so you could consider Kells a Celtic version of the Sistene chapel, with the advantage that you don’t have to strain your neck looking at it.
People were making key patterns long before these monks used them for manuscripts of course, in fact when the artist was painting Kells in the ninth century, there was probably some young monk moaning “Oh, not key patterns, that is like, so third millenium BC…”
(Acrylic on canvas. Probably the last one for a while as they are harder than they look and this is the only one I’ve managed to make properly so far. I’ll have to build up my courage to try another…)