each twelve, every other twelve, or twelve by twelve (see Molina)
Alonso de Molina:
matlatlactli omoome. cada uno doze, o acada doze, o de doze en doze. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 53v. col. 1. Thanks to Joe Campbell for providing the transcription.