Hammer Heads

Two blondes were building a house. one saw that the other was going into her pouch and throwing every other nail out. She thought that this was weird and decided to look into.

"Why do you keep throwing every other nail away?"

"Well, when i pull one out of my pouch, and it is facing towards the house, i nail it it. If it is facing away from the House, it is defective and i throw it away."

"You idiot, those nails aren't defective, they are for the other side of the house."