The moons are split into 28 icons, to correspond neatly with the 28 day moon cycle. There is a primary set and alternate set. The primary set is meant to be interpreted as: where there are pixels, that is the illuminated part of the moon. The alternate set is meant to be interpreted as: where there are pixels, that is the shadowed part of the moon.
Use these special, built-in utility classes to flip, rotate, or assign a fixed width to any icon.
wi-flip-horizontal
wi-flip-vertical
wi-rotate-90
wi-rotate-180
wi-rotate-270
wi-fw