PPC Headquarters is filled with plotholes, both stable and unstable. While these are the most common forms of transport between HQ and other worlds, there are also multiple physical doorways connected to HQ. Each door has a shorthand designation consisting of number-three letters-number. * The first number is the World designation. * The letters are the location the door leads to from headquarters. This usually uses the local language's name for that location. * Any given location can have multiple doorways. The ending number shows where that particular door lies in the series.