As described in Alan Kay's The Reactive Engine, the FLEX (FLexible EXtensible) is a computer designed to be an interactive tool, simple enough to be used by a non-expert, cheap enough to be owned (like a grand piano), and versatile enough to take on various useful forms. Users would interact with it by means of keyboard, line-drawing CRT, and tablet. It would be able to both crunch equations and help create art.
The desire is still to design an interactive tool which can aid in the visualization and realization of provocative notions. It must be simple enough so that one does not have to become a systems programmer (one who understands the arcane rites) to use it. . . . FLEX is an idea debugger and, as such, it is hoped that [it] is also an idea media.