[intrasight]

I do like the "inevitable" test. It ties in with my belief that there are many "inventions" that are universal amongst sentient beings.

[lincolnq]

Off topic, but I am very interested in the topic of what other inventions are universal (I've thought about this myself a bit). Do you have a list or writeup?

[intrasight]

I've not maintained a list over the years. But some that I can name off the top of my head are: Wheel Battery Electric motor Glass LED Laser Book Lens Ballpoint pen Mirror

- you get the idea

[simonh]

My dad claims to have “invented” the brushless electric motor as a physics student, only to discover it had been invented many dozens of times already.

[DaiPlusPlus]

Mathematics