Optimal Battery Box v1.0

This model tries to solve the following problem when organizing batteries: Efficiency: using mathematical optimal pattern to pack most cylindrical cells into a given square shape. Hexagonal packing is only optimal for very large box, but not for smaller ones. This model uses the research of circles packing to maximize number of cells in a given box. Modular: the model contains box for D, C, 9v, AA, AAA, AAAA and CR123d with the same outside dimention, and can be connected with a pin (mortise and tenon joint) to fit it into different containers / drawers. The outside dimension is 80 mm x 80 mm x 12mm and cpacity of the model are 4 D, 6 C, 10 9v, 16 CR123A, 24 AA, 48 AAA, 80 AAAA. I've printed all but D and CR123A models. Please let me know if you notice any problems.