Crochet

I'm trying to work out how to crochet—if you think of astragaloi as the great-grandmothers of modern dice, you'll be right on the money. Envision a rectangular prism; the ends are too small to land on when rolling the thing. The sides are two wide and two narrow, and each pair has one convex and one concave. (I'm not trying to design the crochet pattern any closer than that to actual astragaloi. It's not happening.)

The main design problem here, as you might guess, is keeping the concave sides concave even after sewing the sides together and stuffing the thing with polyfill. I'm wondering if thick-gauge jewelry wire threaded through the stitches would work out okay. But the gauge of the wire would have to work with the gauge of the crochet...

Opinions?