plates are not flat surfaces; instead, they are curved sections of a sphere, which greatly complicates how plate motion is described. In addition, plates usually exhibit some degree of rotational motion, which can cause two locations on the same plate to move at different speeds and in different directions. the latter fact can be illustrated by rotating your dinner plate in a clockwise matter. when doing so you will notice that the items on the left side of the plate move away from you (divergence). Item in the center will rotate, but their position relative to yours will not change. the complex nature of plate motion makes the task of describing plate motions more difficult than simply establishing the relative motion between two plates along the boundary that separates them. Fortunately, using space-age technology, researchers have recently been able to accurately calculate the absolute motion of hundreds of locations across the globe.