“All right. Calm down. Tell me again what happened.”
“Don Pedro, one of my officers is stealing from me. Every day I find out that some of the tools are missing from the workshop, and I do not know which one of them is the thief. Nobody wants to talk and the only utterance that I get from them is ‘I did not take anything from the workshop. I am innocent.’ Can you help me Don Pedro, to discover which one is the guilty one?”
Don Pedro is a strange character from the town, but well respected. His individuality is transmitted by the fact that he likes ducks and particularly his white duck, which he carries with him everywhere he goes.
“I will help you,” said Don Pedro. “Bring every one of your employees here.” Once the employees were assembled, Don Pedro told them: “Inside this room is my duck. It is a magic duck, and by touching it, it will let me know which one of you took the tools that are missing from the workshop. ‘One by one you’ll enter the room, pick up the duck, let it go and leave the room.” That is what happened.
One by one the employees entered the room, did what they were told and left. At the end Don Pedro asked the men to show their hands. All minus one had their hands dirty with chalk, and Don Pedro knew which one was the robber. Because Don Pedro had covered the duck with chalk, every man got their hands dirty, except the one that didn’t dare to touch the duck, afraid that it really had magical powers to reveal his deeds.