The initial two-dimensional representation was coded in the PostScript
language [7]; a PostScript operator named face was
defined, which retrieved the facial parameters from the
operand stack and rendered a face.
To render a face, PostScript code for calling this operator was appended to
the program and it was sent to a printer or piped into GhostScript.
Locally, the operator face called other operators for drawing the local features, such as eyes, mouths, and eyebrows.