Empty but for one star
Imagine the following scene:
A totally empty universe except for a single star.
Read the first comment to see why I find this exercise interesting
Four Zen monks were meditating in a monastery. All of a sudden the prayer flag on the roof started flapping. The younger monk came out of his meditation and said: "Flag is flapping" A more experienced monk said: "Wind is flapping" A third monk who had been there for more than 20 years said: "Mind is flapping." The fourth monk who was the eldest said, visibly annoyed: "Mouths are flapping!"