After I cast the smallbusiness card holder for myself, a number of colleagues asked me to make similar casts for them. One of them asked for a slightly larger version that held more than just business cards. This was the result.
This design was adapted to hold 4"x6" notecards in addition to ordinary business cards.
A powerful magnet was sunk into one side of the cast to serve as a storage point for paperclips. Unlike typical concrete cube "crystals" in most of my other designs with recessed side panels, here the side panels turn the corners in a more modernist way. I haven't yet repeated this idea anywhere else.