Questions on the packing of various (two- or three-dimensional) geometric objects.
Packing is distinct from tiling in that the given shapes may have gaps between them; the goal is often to minimise the relative area of those gaps, or maximise the density. For example, the best packing of equal circles in the plane is $\pi/\sqrt{12}=0.907$, and that of equal spheres $\pi/(3\sqrt2)=0.740$ (the content of Hales's theorem). Packing within a bounded region poses very different challenges due to the boundaries and is an active research topic. geometry is often paired with this tag.
