I'm in a new subdivision, and each home has rock walls, typical for the area. They are building a wall right now between me and the next house (which I am very happy about).

I'm wondering if I can sneak in some decorative elements on my side right where the windows look out, now when the mortar is new. Something like little tiles, small mirrors, etc. Just for some visual interest. I don't know if the builder would go for it, but on my side, it's my wall, right?