So they go out and buy the materials and return home to do the job. They decide it would be best for the first blonde to work on the front and the second on the back.
After about an hour the first blonde goes to the back to see how it’s coming and watches as the other blonde picks up a nail and drive in, then pick up another nail and throws it on the ground and continues this repeatedly.
The first blonde yells “Why are you throwing good nails on the ground?”
The second blonde replies “They are defective! The pointy ends are pointing the wrong way.”
“You idiot!” Shouts the first blonde. “Those are for the other side of the house. “