> vaguely cubical

Well, a cube is an abstract geometrical shape, whereas spheres and spirals are natural facts found everywhere. A sphere is a decidedly simple and highly efficient form, a box is not - unless you want something to *not roll anywhere:-)
Your comment illuminates the interesting interplay between two basic personality types though: the very boxy, prickly ones versus the well-rounded<g>, touchy-feely ones. The difference here is not one of varying view points of course, but a question of one's focus or resolution.