Chiastic Phrases and Their Ability to Convey Profundities - Serious or Humorous.

We have always come across interesting phrases and twists of words. Recently, my brother mentioned, in the context of healthy living, that we should engage activities that add

"life to years, and
not years to life". 

Then, of course, there is this one that I found on a university campus:

A good man is hard to find,
A hard man is good to find.

What do both of these foregoing phrases have in common? A figure of speech, by which the order of the terms in the first of two parallel clauses is reversed in the second, but with some interesting meaning. In the first example, there is a suggestion as to how to live life. The second one is a humorous twist provided by a college student on a modern day proverb that describes how difficult it is to find a [male] partner. (The difficulty is obviously applicable to the female version too, but no one has created that version yet).

Turns out that our linguist friends have even a name for this kind of figure of speech: Chiasmus.