> How did he encode what the neighboring countries are?

See https://en.wikipedia.org/wiki/Syria

https://en.wikipedia.org/wiki/Syria#/media/File:Syria_(ortho...

That map of the globe is what we use as the front of the card

He sees that and knows the answer is Syria.

But because we also do that for the other countries around it, he knows Turkey, Iraq, Jordan, Lebanon, etc. He knows where that country is, in context of its neighbors.

We have some little mnemonics to remember things like, "I packed my bags in Pakistan. After that, Afghanistan. Then Iraaaan all the way til I hit a rock in Iraq."