Below is a collection of Ptolemy II models illustrating various modeling issues with cyber-physical systems (CPSs), using a portion of a vehicle-management systems (VMS) that manages multiple fuel tanks in an aircraft as an example. The details of how these models illustrate modeling issues are covered in the paper "Modeling Cyber-Physical Systems," by Derler, Lee, Sangiovanni Vincentelli, which is to appear. That paper includes hyperlinks to some of these models.