PLATO
PLATO (Programmed Logic for Automatic Teaching Operations) was the first generalized computer assisted instruction or distance system. It began in 1960, running ran on the University of Illinois' ILLIAC I computer. By the late 1970s, it supported several thousand graphics terminals distributed worldwide, running on nearly a dozen different networked mainframe computers.
Because the system needed a low cost graphic display, the PLATO project engineers developed the plasma panel, which was very useful for its inherent memory. PLATO's plasma displays produced orange colored graphics and the background color was either black or a color slide that was displayed using the projector built into every terminal.
PLATO IV terminals also featured an early touch screen that was implemented by a user's finger breaking the infrared light beams that traversed the display panel.