Business Card Holder

I wanted a business card holder, but the designs I found were either wasteful (full discs) or fragile (I broke the teeth of several other ones just removing it from my printer bed).

So I made a more sturdy one, in two shapes (half-circle cross sections and half-oval cross section) and 2 different card sets (36 and 24 cards). The slots are 1mm wide on all models.