A man walks into a bar and orders a drink. As he's sitting there, he notices a sign behind the bar that says, "Free drinks for life if you can pass our challenge."
Intrigued, the man asks the bartender about the challenge. The bartender explains that all he has to do is walk across the room and jump out the window, and if he can land on his feet outside, he'll get free drinks for life.
The man thinks about it for a moment and then decides to give it a try. He walks to the other side of the room, takes a deep breath, and jumps out the window. Miraculously, he lands on his feet outside!
The bartender is amazed and asks the man how he did it. The man replies, "Well, I've been practicing for years. You see, I used to work for a company that made windows."