I remember many years ago when "in the spirit of Vatican 2" our high school invited a practitioner of zen to give a talk as part of a series on different religions.
Here are some of the nebulous answers we were given:
"Zen is the sound of no hands clapping"
"Zen is the shade under an oak tree"
This same wacko related to us some stories about "attaining enlightenment"...
"Before you attain enlightenment mountains are mountains and rivers are rivers. While you're in the process of enlightment, mountains are no longer mountains and rivers are no longer rivers. Once you attain enlightment, mountains are once again mountains and rivers are once again rivers".
"In their quest for enlightment 2 young men sat staring at a flag-pole for over a week. Finally one of them said, "The flag is moving". Some time later the other responded, "No, it is the wind that is moving". Finally, a master of zen who had been watching the 2 men corrected them both, "No, it is your mind that is moving" - and they were instantly enlightened".
Go figure.