The main panel in the centre of the NIMROD facade displayed the play of the game to the spectators.
The rows of lights in the top portion simply echoed the lights on the Control Desk for their benefit.
Below these, one of these legends would be illuminated to show the stages of the game:
The bottom one would only be seen during slow or manual operation
of the computer. In normal play its move was essentially instantaneous.
However, the button on the control desk always had to be pressed to
initiate its move, hence the need for the legend above it.