"Okay" says the gym teacher, "Everyone line up, boys on one side, girls on the other".
The cisgender person lines up.
The transgender person moves from the line they were told to be in to the line they identify with.
The bigender person runs back and forth from one line to the other.
The gender fluid person runs in circles, screaming.
The agender person says "So long, suckers" and goes home.