Turning Negatives Into Positives

We often hear that a double negative makes a positive ("He was not incompetent" translates weakly into "He has competence" although it suggests there is some other problem). I looked up the "double negative" definition and information and it turns out there is WAY too much of it for me to post about here. Suffice it to say, a double negative can be positive, or negative, or even neutral. Language is like that. I'm not a grammarian nor do I pretend to play one in any capacity. 

From Wikipedia: Historically, Chaucer made extensive use of double, triple, and even quadruple negatives in his Canterbury Tales. About the Friar, he writes "Ther nas no man no wher so vertuous" ("There never was no man nowhere so virtuous"). About the Knight, "He nevere yet no vileynye ne sayde / In all his lyf unto no maner wight" ("He never yet no vileness didn't say / In all his life to no manner of man").

I do toy with the idea of creating a dictionary for concepts the English language lacks words for. There are so many! For example: What is the word for a parent whose child has died? As far as I'm aware, there isn't such a term, and we need one.

The following image is what triggered my musings on double negatives.

This little poster is intended to be positive and encouraging. For me, the most clear message is that the creator reached out of the bowels of Hell to convey a message of hope. Despite a deluge of double negatives and weak language, the bottom line floats in the rain gutter: Keep going - light is on its way.