Drawing based on:
Shield used by the inhabitants of the city of Azcapotzalco in the colony, as a sign of his nobility, this shield was never officially recognized by colonial authority or independent Mexico, but is commonly found in documents and town houses,
http://dialnet.unirioja.es/servlet/fichero_articulo?codigo=1456108&amp;orden=0  pag. 7
http://pueblosoriginarios.com/meso/valle/tepaneca/tepaneca.html

http://pueblosoriginarios.com/meso/valle/tepaneca/imagenes/codice.jpg
Own work
Sarumo74