The Pedagogy of Riddles

In zen buddhism, the means to enlightenment, to transformational change, is solving an unsolvable riddle called a koan.

For example, "what is the sound of one hand clapping?"
For example, "what is the color of the wind?"

All of their usual intellectual techniques are frustrated. The riddle is designed to have no logical answer. It is given by an authority figure, who confidently explains that it does have a meaning, that he/she knows the meaning, but that there is no benefit from being told the meaning.

the only benefit is from unraveling the mystery oneself.

Now the naive perspective thinks this is crazy. How could the answer not be the important part? And there are a bunch of typical attempts to avoid doing the work.

Well this is just like reading a novel to determine it's "meaning."

I've heard somewhere that Abraham Lincoln's favorite riddle went as follows: how many legs does a dog have if you call the tail a leg?

The answer is four. What you call something doesn't change what it is... But by saying that so quickly, I changed one thing. Your level of participation. Your level of involvement.

Consider these points.
1. The phenomenon of teaching tales is prevalent in almost every culture.
2. We value ambiguity in literature. Why? Why don't we read Harry Potter books or John Grisham novels?