My friends live near me but we don’t all use the same subway stop. When we need to meet up to go somewhere together we’ll often agree to meet on a train.
We agree on a time to meet at a specific stop, each person figuring out what that means for their departure from their stop.
It’s like that middle school math problem: the one about trains leaving and when they’ll cross paths…
Calculate correctly and a head pops out a door or you spot the arriving person waving as the train pulls in and its a seamless meet up.
Miscalculation means you have to get off the train and wait.
Masters of this game know to also factor in that outlier element: your friends tendency to always be late.
I like to be the one on the incoming train because I’m guilty of always running late and because I make a game of guessing how quickly I’ll spot my friend.