A/B Testing: Two boards. Two nails. Two hammers, but one hammer has a really long handle and the other has no handle.
Acceptance Testing: The nail is tapped by the end of the handle of the hammer lightly enough that the nail doesn't budge. The final panel is just the words "make it work."
Penetration Testing: A claw hammer in a balaclava and white top hat pulls the the nail out of the board and sneaks off out of the panel with the nail.