What is a Metaphor?

What is a Metaphor
Imagine, briefly:

A set of parallel bars.

Where one goes, the other follows.
Where one terminates, so too does the other.

It takes an existential gymnast to balance
with just two hands and one bar.

It takes but a human to balance
with bars in parallel.

Perhaps a little strength is required,
but that’s a life-requisite anyways.

So, to address the titular motivation:
What is a Metaphor?

A metaphor
Gives balance

Where, with but one understanding,
we might fall hard to the floor.