Fart

I just did a number two fart.

Loud and unsmelly.

1 = silent and unsmelly. You can't hear it or see it, so there is no problem whatsoever.
2 = loud and unsmelly. You can hear it coming, but it doesn't get you. Also, you can tell who did it, just in case you want to blame somebody.
3 = loud and smelly. You can hear it coming, and it gets you. At least you know who did it.
4 = silent and smelly. This one is wicked. You can't prepare for it. It just gets you without warning. Plus, you can't tell who did it, and you might even get blamed for it. Someone gets off without blame for this deadly puff.

Wicked!