An old parchment describes the location of buried treasure:
"On the island there are only two trees, A and B, and the remains of a gallows. Start at the gallows and count the steps required to walk in a straight line to tree A. At the tree turn 90 degrees to the left and then walk forward the same number of steps. At the point where you top drive a spike into the ground. Now return to the gallows and walk in a straight line, counting your steps, to tree B. When you reach the tree, turn 90 degrees to the right and take the same number of steps forward, placing another spike at the point where you stop. Dig at the point exactly halfway between the spikes and you will find the treasure."
However, our hero when he gets to the island finds the gallows missing. Is there any way he can still get to the treasure?
A simple experiment with a ruler and paper shows that any position for the gallows leads to the same point.