Martha CrimsonOh. It's a rug. Well, that works too, but I what I first saw was a ginormous, glorious _tile_. And I kinda' wanted to copy it for future projects*.
Normally when canon rubs you the wrong way you solve it with fanfiction AU, but for tiles? I don't read fanfics, so I have no idea whether the masonry section on AO3 is bustling with activity or not.
(*Don't laugh! I'll definitely get to them any other millenia or so!)