Using 3D design to teach a math concept

I like cooperative learning games. I have used something like this made out of laminated paper in the past, so I wanted to see how hard it was to design a prototype for the 3D printer. This is only a 3 inch prototype model because I had to scale it down to fit on my school's 3D printer. That's OK, because prototypes of the second or third try are not generally printed full-scale. As it is shown here, the plus and equals spots are too small to fit a pen or wood pencil, and the squares are too small for the unit squares aka ones blocks in the base ten block manipulatives that are everywhere in most elementary schools. So for demo purposes, we used beads.

https://www.thingiverse.com/thing:2960454