nan
-1 negative -------
-2 negativer
- 0 zero ------------=-|
- .0 zeroer ------------=-|
--00 zeroest ------------=-|
+ 0 zero -----------<=-|
+ .0 zeroer -----------<=-|
+-00 zeroest -----------<=-|
-1.5 positive ------------=-|-----------
+1.5 positive -----------<=-|-----------