At intercambio on Saturday, one of the people I was seated with suggested we use a coin (mine) to do águila o sol to decide whether we started the two hours with an hour of English (or Spanish). I didn’t care, but he did. He wanted English first; he even had a book he wanted us to translate.
He tossed the coin and also called it: águila. I wouldn’t have known the difference.
I confirmed with several parties that the denomination side is the sun; it is based on an Aztec sun. The eagle seems as blurry to my eyes as the picture I have provided.