@Starhawk (18 June, 2016, 6:19 AM UTC):
Darkness is simply the absence of light.

Imagine light and dark as a line of people running at the same speed. (Not to be sexist or anything, but) To simplify this, boys will be leading as "light" and an infinite amount of girls following as "dark". (If there's another beam of light, there are boys replacing where the girls would be)

So when the boys reach a doorway (That they go through without slowing), you would see their effect (of light reflecting), then when all the boys have gone through, you see all the girls following them (And there is no more reflection as there are no more boys).

As for the towel part, I'm pretty sure water brings some of the dirt and such from inside your skin (pores) to the surface, where it's a bit more difficult for the water to remove (And doesn't remove all of it), so the towel takes that off your hands (Literally and figuratively :P)

Also moved this to off-topic since this doesn't really have anything to do with the game.

@Starhawk (20 June, 2016, 7:06 PM UTC):
Both :P

But there is no way to prove whether I am truthful or not... Lie detectors can fail.... People can lie... Even a person's mind can lie to themselves... So we may never know what is true... o.O

Also, I used Bing. Because I can. Or do I? o.O

Probably. lol