Writing and drawing together on a common display often assist a working group in a task. For example,face-to-face groups have long enjoyed the richness of graphic communication found on blackboards. The spontaneous image manipulations which take place over time on a blackboard can be viewed as a text-graphic performance. A human performer generates and manipulates text and graphics for the purpose of assisting the working group in their task.The phenomenon of performed text-graphics presents opportunities for research in the area of computer-supported cooperative work. 1] Spontaneous generation demands a performing medium where the focus is on live manipulation of text and graphics. Design of a computer-based medium with enough agility and generality to support blackboard-like activity is a challenge for interface design. 2] Agility and generality must not be achieved at the expense of specializability. After a group has initially sketched an idea in text and graphics, then that same medium should also support refining the sketch according to formal schema. 3] The performing medium can also be used as a recording medium for studying image manipulation as part of the working group process.This paper presents a stepwise approach to the design of a performing medium for working group graphics. First, examples of non-computer text-graphics for groups are examined to get a preliminary idea of the underlying phenomenon: the performing of text-graphic manipulation to assist working groups. Next key features of that kind of text-graphic manipulation are isolated. Then, third, the architecture and behavior of a graphics editor providing those features is described.

The general purpose graphics systems of the future will need a simple logic for visual objects—one structure underlying both text and graphics. As an experiment, perhaps the immediate handling of visual objects by the user can provide the starting point for developing that structure. This paper describes the PAM graphics system, in which the structure of text-graphic objects arises directly out of manual manipulation. The needs of manual manipulation determine the text-graphic pattern as the simplest organizing structure for images; PAM stands for PAttern Manipulating. The PAM system is designed for the agile manipulation of text-graphic patterns—first manually, and then, later, programmatically.Starting from this strict 'front-in' viewpoint—where immediate manipulation (hand powered animation) was to be the primary application—a 'manipulative grammar' was evolved to give the user a simple yet powerful handle on text-graphic images. This grammar turned out to be a generalization of LISP syntax from textual symbolic expressions to text-graphic forms, structuring such forms as trees and then offering: