Only thing that I might add is that a simple " X " can mean the flag of many countries until you add the color.
That actually might be kind of cool. The saltire, or x-shaped cross, is found on a flag associated with Ireland, the St. Patrick's Cross, as well as a Russian flag, since St. Andrew is one of the patron saints of Russia. It's also found on several US state flags, Nova Scotia in Canada, and one of the Channel Islands, Jersey.

And, the Welsh and the Cornish, twa Celtic people's, use a cross as well, the St. David's cross (gold on black) and the St. Piran's cross (white on black), respectively.

just a thought...

Cheers,

T.