I wrote the original PED program at AT&T Bell Labs during 1982-84. PED was a distributed program, part of it running on the bitmap terminal Blit and the rest on a VAX machine. While PED has been surpassed by other drawing programs written in more recent years, it had some features that are absent from the currently available programs, including the ability to draw free hand and then "beautify" drawings. (See T. Pavlidis and C. J. Van Wyk ``An Automatic Beautifier for Drawings and Illustrations,'' Proceedings of SIGGRAPH'85, San Francisco, July 22-26, 1985, pp. 225-234).
Because the program was tied to the Blit that found few customers outside AT&T, its only users were within AT&T. On the other hand AT&T was a very large company at the time (this was before the divestiture), so that PED had several hundreds of users (if not more). To the best of my knowledge, the westernmost place where PED was used was Denver and the easternmost the Netherlands (in a joint AT&T-Philips venture). (See The Unix Time-Sharing System - Programmer's Manual, Ninth Edition, vol. 1, September 1986, Section 9.1. Also T. Pavlidis PED User's Manual, Bell Labs Computer Science Technical Report 110, 1984. )