Ah - good old BBC Basic! I taught myself how to program in that - and wrote programs to calculate turn keys for fighter intercepts for any ABH, interceptor TAS and target TAS!
Later I derived equations to describe all tanker RV procedures with any input variables of roll-out range, overtake speed, TAS, tanker and receiver bank angles. I then wrote up the results; to his day they're used as the official values in the NATO Air Refuelling Document ATP-56A.
My reward from a generous air force? Nothing - not a bean nor even a single word of thanks. Yet I knew I'd saved them wasting £25000 to have a civilian software consultant do the job for them.
I'm older and wiser now! I remember hammering out the equations, checking them with my trusty Texas Instruments calculator and writing the programs late into the night at the very kitchen table where I'm tapping away right now! Never, never give your work away to such an ungrateful employer!