Where can I find a square stackable shelf (cabinet?) with no door or back? Or one shapes like a staircase?

Question:I am looking for a modern shelf shapes like a stair case. The one you can also use as a partition. Or cubic stackable shelf without door or back? Any idea?

Answers:
You can find the stair-look ones at:

Bombay (and Bombay Outlet)
JC Penney
Ballard Design
Pottery Barn

I also saw the cube with the open back at one of those stores (online).