Zometool
is a building system consisting of a variety or rods that can be slotted into balls at a variety of angles. It provides much more construction flexibility than the building toys you may have encountered as a child. For example, the structure in the first image is a projection onto three dimensions of a truncated 600-cell. I helped build these models in January 2004.
(The second picture is much better quality on my computer, but for some reason seems to have issues when I post it.)
