It is possible this isn't wallpaper. It could be those vinyl stick on wall decals.
There are many websites that have them. I thought I saved some of them in my favorites but can't find them. just search for 'wall decals'.

Could also be a stencil

It can be either painted or wall decals. Most likely a wall decal, definitely not a wall paper. If you are interested in getting similar wall decal, we can do that for you in any size and any color (24 colors available). Feel free to browse through our wall decal collection at our Etsy store: http://www.etsy.com/shop/Decaleco. We have done many custom designs for our customers and they love the high quality material we use to make the decals (the decals look just like paint on their walls and they are removable, without leaving residues on the walls).

i'd like to find these wall stencils

I like this floor type, what is it ?