Q: What do you get when you cross a Zen Master with a Druid?

 A: Someone who worships the tree that is not there!
 

 Q: How about when you cross a Zen Master with a Druid veternarian?

 A: Someone who worships the bark of the tree that is not there!
 

 Q: Or when you cross a Zen Master with a Druid mathematician?

 A: Someone who worships the square root of the tree that is not there.