I always have a hard time remembering pi past 3.14 but this pie makes it easy because I see pictures in my brain, I can look see 3.14159 any time I want.
Tell us about those rare occasions !
I seriously question any circumstance in engineering where you need 18 digits. How accurately do you know the yield strength of the steel your using, the value of the capacitor in your circuit, the fuel flow rate in your engine? Can you really measure your distances in meters to 1/100 the size of a proton?Perhaps https://en.wikipedia.org/wiki/Piphilology has a useful sequence?.
As a young mind I was able to do around 50 decimals if I trained often enough (that was without any particual memo-technique). Now, all those years later, the first 18 has somehow gotten stuck in memory and since I rarely need more than that as an engineer I'm quite happy I put in the effort back then
They got Buzz and Neil to the moon and back. Lots of impressive stuff was built with 3 significant digits, back in the day. Granted not as impressive as what consumers can buy today. No LHC or LIGO in 1970.Engineers use slide rules
I seriously question any circumstance in engineering where you need 18 digits.
No they didn't. There is a good account of the pre-flight computations as well as the real time actions and post-flight analysis at https://history.nasa.gov/afj/index.html.[Slide rules] got Buzz and Neil to the moon and back. Lots of impressive stuff was built with 3 significant digits, back in the day.