Professor Knot was very proud of his collection of paintings that were hanging on all the walls in his apartment. Our story begins when a neighbor from a nearby apartment started indoor reconstruction. The walls were shaking because of vibration. Professor was worried for safety of his paintings and decided to add one or even two nails.
And, he did it! First picture was hanging on two hooks.
Then he wanted to increase the safety and wrapped the rope several times, as shown in figure.
After that , he was quite satisfied.
Anyway, he decided to test security by pooling out one of the two hooks. He first pool out the right hook.
He was very surprised when the picture fell down on the floor! This means that the left hook does not hold a picture. Meaning: right hook keeps all the weight. He wanted to be sure.
Than, he repeated the whole procedure and picture was hanging on the wall, holding on two nails.
This time he pulled out the left hook because the right one holding a picture . He almost fainted when the picture fell down on the floor, again.
If neither the left nor the right hook does not hold a picture, what holds the picture?
Prepared by Zorica Marinković based on article “Boromejski prstenovi ili Kako umetnički okačiti sliku“, Rade T. Živaljević, Časopis Tangenta 59/3, 2009-2010