Alley mural, SE 6th & Yamhill

So our next stop on the mural tour is a little unusual. The block bordered by SE 6th & 7th Ave., & Yamhill & Taylor Sts. is home to several older buildings, with narrow alleys between them. Alleys like this in Portland are almost always fenced off, but these aren't (at least not yet), and the one facing 6th contains the mural you see here. It doesn't appear to be signed, and I don't know anything about it; I just happened to notice it while walking by, so I stopped for a few photos. It kind of looks like a Mayan design to me, but I'm not an expert on pre-Columbian art, and it could just as easily be an Aztec or Olmec pattern, or something invented for this mural for all I know.