Even though it was now middle of winter, Jack hauled out his ladder and placed his ladder against the side of the house and began to climb. He had some bad luck when he reached the half-way point. The ground was a frozen sheet of ice and the base of his ladder slipped out and the top slid down the side of the house. Jack, clinging to the center rung, wound up moving from Point A on the side of his house to Point B on the ground.
Describe the path Jack traveled.
...someone were to pick up the end of the ladder that was away from the house and lift it back up against the house with Jack still on it. Jack would retrace his path (except, off course, now he'd be on the wrong side of the ladder :-)
Now, suppose...
