Classic Lateral-Thinking Exercise 1. There is a man that lives on the top floor of a very tall building. Everyday he gets the elevator down to the ground floor to leave the building to go to work. Upon returning from work though, he can only travel half way up in the lift and has to walk the rest of the way unless it's raining! WHY? * This is probably the best known and most celebrated of all lateral-thinking puzzles. It is a true classic. Although there are many possible solutions, which fit the initial conditions, only the canonical answer is truly satisfying. ********** 2. A man and his son are in a car accident. The father dies on the scene, but the child is rushed to the hospital. When he arrives the surgeon says "I can't operate on this boy, he is my son!" How can this be? ********** 3. A man is wearing black. Black shoes, socks, trousers, jumper, gloves and balaclava. He is walking down a black street with all the street lamps off. A black car is coming towards him with its light off too but somehow manages to stop in time. How did the driver see the man? ********** 4. Title : The Elder Twin One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. Why? *********** 5. Title : Manhole Covers Why is it better to have round manhole covers than square ones? * This is logical rather than lateral, but it is a good puzzle which can be solved by lateral thinking techniques. It is supposedly used by a very well known software company as an interview question for prospective employees. ************ 6. Title : The Deadly Party A man went to a party and drank some of the punch. He then left early. Everyone else at the party who drank the punch subsequently died of poisoning. Why did the man not die? ************ 7. Title : Heaven A man died and went to Heaven. There were thousands of other people there. They were all naked and all looked as they did at the age of 21. He looked around to see if there was anyone he recognized. He saw a couple and he knew immediately that they were Adam and Eve. How did he know? ************* 8. Title : Trouble with Sons A woman had two sons who were born on the same hour of the same day of the same year. But they were not twins. How could this be so? ************* 9. Title : The Man in the Bar A man walks into a bar and asks the barman for a glass of water. The barman pulls out a gun and points it at the man. The man says 'Thank you' and walks out. * This puzzle has claims to be the best of the genre. It is simple in its statement, absolutely baffling and yet with a completely satisfying solution. Most people struggle very hard to solve this one yet they like the answer when they hear it or have the satisfaction of figuring it out. ********************************************* SOLUTIONS: 1) The man is very very short and so can only reach half way up the lift buttons! However, if it is raining then he will have his umbrella with him and so can press the higher buttons with it. 2) The surgeon is the boy's mother. 3) It was daytime. 4) At the time she went into labor, the mother of the twins was travelling by plane. The older twin, Terry, was born first early on March 1st. The plane then crossed a time zone and Kerry, the younger twin, was born on February the 28th. Therefore, the younger twin celebrates her birthday two days before her older brother. 5) A square manhole cover can be turned and dropped down the diagonal of the manhole. A round manhole cannot be dropped down the manhole. So for safety and practicality, all manhole covers should be round. 6) The poison in the punch came from the ice cubes. When the man drank the punch, the ice was fully frozen and was just placed in the punch. Gradually it melted, poisoning the punch. 7) He recognized Adam and Eve as the only people without navels. Because they were not born of women, they had never had umbilical cords and therefore they never had navels. This one seems perfectly logical but it can sometimes spark fierce theological arguments. 8) They were two of a set of triplets (or quadruplets etc.) * This puzzle stumps many people. They try outlandish solutions involving test-tube babies or surrogate mothers. Why does the brain search for complex solutions when there is a much simpler one available? 9) The man had hiccups. The barman recognized this from his speech and drew the gun in order to give him a shock. It worked and cured the hiccups, so the man no longer needed the water. * This is a simple puzzle to state but a difficult one to solve. It is a perfect example of a seemingly irrational situation having a simple and complete explanation. Amazingly this classic puzzle seems to work in different cultures and languages.