"Visible from the public street" seems to be equivalent to "located in a public place" at least under Section 120. But tiling. Hmmm.... I offered a class in tessellation theory recently and discovered to my dismay that one of the Penrose tilings was apparently in some way protected (I never verified this, but as the story goes, some college wanted to tile the floor of a new math building with a Penrose tiling and couldn't). Assuming the tiling is interesting not for its qualities as a mosaic (owing to the arrangement of colors in locations), but rather for a curious pattern of polygons in two-space, then we may be in a different realm. Since tilings may be organized into symmetry groups, they become rather like facts. There is the (33344) tiling and the (33434) tiling -- see for example, the background used at http://www.williams.edu:803/Individuals/ddailey. I suspect most "normal" tilings (like the square or hex grids) are absolutely unprotected, having been independently discovered/invented by numerous cultures in antiquity. But, as the metallurgical and computational uses of nondeterministic tilings become more ubiquitous, the urge to protect these items will clearly grow. And yes, there are undecidable problems embedded in the theory of tiling, so one can create "monster" tilings of the sort that make Russell, Frege, and Whitehead queasy. So I guess if the tiling is not "too interesting," then it is photographable.