This guide is conceptual and visual about mesoamericans cultures, this in order don't make mistakes like others RTS representing the culture of the ancient of the land where I'm ( Honduras in my case).
You can use butterfly design @LordGood
https://books.google.com.ar/books?id=dntoT_MdGWsC&pg=PA153&lpg=PA153&dq=mesoamerican+shields+-aztec&source=bl&ots=LXoayRW38c&sig=zMCI1lydEa7kycaP8SqYctLboq4&hl=es-419&sa=X&ved=0ahUKEwjB4sijj5DRAhXBJCYKHaISDMcQ6AEIJjAE#v=onepage&q=mesoamerican shields -aztec&f=false