If you've been following the last few entries, you know that I was riding along North Fontana Ave. on May 20 of last year. And if you've already seen today's entry on the Tucson Murals Project blog, you'll know that there are handpainted murals on the porch. (If you missed it, click there.)
And here you can see the box. It's black, on a dark post set with square and rectangular tiles.