So, that's where I started my Wikipedia trail:
Triskelion. This is a design that has three interlocked spirals or bent legs (like in the flag). It is not just the symbol of the Isle of Man, but also Sicily. The article gives ancient and modern examples from Europe and Asia too. It is also a Kumyk symbol, so I need to look that up next.
Khazars. The medieval Khazar kingdom was one of the most powerful states on the Silk Road. The article includes a discussion of the King of the Khazars and their mass conversion to Judaism, which is how I know about the Khazars: that legendary conversion is a big theme in Milorad Pavic's Dictionary of the Khazars, one of my favorite books!