Quote from the solution:
Now the medieval castles had spiral stairwells that when viewed from the bottom climbed the inside tower wall in a counter-clockwise direction. However, Mrs. Bottomfeeder’s stairs climbed the tower wall in a clockwise direction.
So imagine you are the princess and the castle is under attack. You are in the tower. The attackers are coming up the stairs and wielding their swords in their right hands. If the tower was built correctly, in a counter-clockwise direction, the attackers would find it difficult to swing their swords freely because the wall was on their right side. And the wall would be in their way. But the princess’s defenders coming down the staircase would have no such impediment, and would have a clear advantage.
I submit that it should be the opposite, i.e., viewed (or looking up) from the bottom, the staircase should rise in a clockwise direction.