These are a set of nine “L”-shaped erasers from Seed of Japan. (Shown on Strathmore 400 Series Artagain black paper.)
The nine erasers together form a 3x3x3 cube. If you search the web, you’ll see that this is an example of a range of tiling/puzzle/cube problems that have attracted interest over the years. Mathematician John Conway is especially well known in this area.
Though interesting, I wish that the eraser pattern was a little more challenging to reassemble.
The erasers are good quality white vinyl, though probably impractical for frequent use. Of course with the pieces scattered on your desk, one will likely always be in sight, so there are merits.
If you like this sort of amusement, here’s my favorite online tile puzzle: Quzzle. I’ve neither solved it nor lost interest.
I also recommend browsing around the Seed site if you’re interested in erasers. They appear to have some very interesting products which unfortunately aren’t yet widely available outside Japan.