
...between the number of chirps PER
minute and the ambient temPERature.
The Big Bang Theory Season 3, Episode 2

We're melting 52 ingots PER hour.
Money Heist Season 3, Episode 5

of 4.6 yoctometers
PER femtosecond.
The Big Bang Theory Season 5, Episode 18

has to be four revolutions PER second.
The Big Bang Theory Season 10, Episode 20

show a part PER
million deviation.
The Big Bang Theory Season 12, Episode 18