I found this a couple of blocks from Panaderia Lillys. No explanation visible on the outside. Realizing that there was a bit of risk, I ran the QR reader on my phone on these. It leads to some way-out-there art organization, I think. The panel on the left brings up a web page with little on it, that I could tell. The second leads to a kinda-sorta video where not much happens. I may look up the URL later if I have nothing better to do. And my phone hasn't locked up so far.