Phyllis Fox is an American mathematician and computer scientist.
She was part of the team that wrote DYNAMO

DYNAMO (programming language)

DYNAMO was a simulation language and accompanying graphical notation developed within the system dynamics analytical framework...

 for Jay Forrester's system dynamics

System dynamics

System dynamics is an approach to understanding the behaviour of complex systems over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system. What makes using system dynamics different from other approaches to studying complex systems is the use...

 research group. She then became a collaborator on the first LISP

Lisp

A lisp is a speech impediment, historically also known as sigmatism. Stereotypically, people with a lisp are unable to pronounce sibilants , and replace them with interdentals , though there are actually several kinds of lisp...

 interpreter, and the principal author of the first LISP manual.

After a stint as a tenured professor, she moved to Bell Labs

Bell Labs

Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...

to work on a highly portable numerics library (PORT).