Are you sure it's Styrofoam? I've always found it hard to glue things to Styrofoam, and the uncovered ball at the bottom looks more substantial than Styrofoam - more like wood, actually.
Regardless, they look cool. I think it would be a great project as a wall covering. Make one good-sized square, scan it, erase the visible seams, replicate it on the right paper and you've got a kickass wallpaper.
I'm not sure about the Styrofoam, I used Google Translate and in the comments at the bottom Kete mentions Styrofoam, but GT and Chinese doesn't make to much sense I find.. though some of the balls looks like wood, but others like Styrofoam
But your idea for a wallpaper - so cool!