Because of the conductor.
Prism
The stone to throw the lights out, the flashlight to check if the lights are really out
Better question would be: Why were they in the tree in the first place?
It's rear end!
A school teacher tells you to spit out your gum, a train says choo choo.
Because they didn't want to wait 40 years for a train!
The conductor.
One trains the mind the other minds the train.
