The E and S rack was an 'image generator'. That one was called an SP1. I fondly remember the SP3T as being the pinnacle of that series; the T meant "texture processing".

image a computer display made up of 1000 line segments. that is what you would get. it was possible to buy these with an output that was not raster, rather it drew on the CRT with vector segments. incredible light points to simulate night landings.