From Wikipedia:

*In mathematics, the four color theorem, or the four color map theorem, states that, given any separation of a plane into contiguous regions, producing a figure called a map, no more than four colors are required to color the regions of the map so that no two adjacent regions have the same color.*

I assume that this theorem doesn't apply to 3D objects, because each "region" could be touching every other region. Is there any kind of related theorem that applies to 3D objects?