A lead for providing electrical stimulation of patient tissue includes a distal lead element, at least two proximal lead elements, and a junction coupling the distal lead element to each of the at least two proximal lead elements. The pump has an inlet for receiving fluid, an outlet for discharging pressurized fluid, and a pump displacement input. For example, a screen buffer or visual representation of a new version of a software application can be compared with those representations generated using one or more previously released software versions of that application.