Various elements of the system chassis 200 or components thereof are illustrated in multiple figures. As elements are described below, one or a few figures which are thought to be particularly pertinent to the element being described will be noted, and thus the description below will not necessarily describe FIGS. 2-7 separately and in strict sequence but will instead move back and forth between various figures. In addition, it should be understood that when certain figures are referred to in relation to a particular element, other figures besides those that are identified may also illustrate the same part from other perspectives.