In high school our computer class was in BASIC. They taught us to swap two variables A & B like this:
h = a
a = b
b = h
But I knew the BASIC we used had the SWAP command. On an exam, I used SWAP A,B instead of the above. I got the lowest passing score, a 70%, and the teacher wrote, "Do it our way please". No thanks Mrs. Mott, I'll take the 70.
I'm not sure how much he actually used it after I wrote it for him, to be honest! But we did have access to daily newspapers, and some of us got weekly stock charts called "Daily Charts" by Investor's Business Daily (all paper, of course). Some of us were into trading stocks (this was during the Internet boom 1995-2000). Another weird skill I learned that is still useful to this day.
I served 60 months of the 70 month sentence. I had a computer restriction, so I couldn't be around a computer.
Since I wasn't able to use computers or the Internet for that time, I did/read/learned a lot of things I wouldn't have otherwise learned. Learned how to make hooch (prison wine), how the law works and how to maneuver the court system (useful for both civil and criminal cases), got more fluent in French by speaking with some native French speakers from Benin, learned how to work out & lift weights (which I still do), and learned the value of freedom.
My TI-85 story. While I was in prison, around 1996 or 1997, I found out a friend had a TI-85 calculator. I realized it was programmable, so I borrowed it over the weekend and wrote a program to track his stock portfolio. It was the first time I had programmed anything in 2 or 3 years.
Then I learned that the US Bureau of Prisons had a rule against any calculator (or device) that was "programmable". So I programmed the TI-85 so its startup screen read, "TI-85 NON-PROGRAMMABLE CALCULATOR". Problem solved.
But I knew the BASIC we used had the SWAP command. On an exam, I used SWAP A,B instead of the above. I got the lowest passing score, a 70%, and the teacher wrote, "Do it our way please". No thanks Mrs. Mott, I'll take the 70.