They had come up with a neat solution involving really tight depth of field and doubly exposed file with two different colour filters a short time apart. So we had a slice though the droplet cloud.
I was told oh we have brought an A0 digitizer (costing about twice my salary at the time) work out how to interface to that PDP and develop a system to locate the droplets in the xy plane.
To solve that you actually have to know real engineering to get this to work the actual programming is the easy bit. I also had to work out how to write a interrupt driven driver to interface the tablet to the computer – Luckily RT11 did have some basic multitasking functionality built into it.
PS we did also use prolog on other projects so it does have its uses