Classic Lateral Thinking Exercises

Test yourself with these thinking excercises. The solutions are at the bottom of the page. Don't be lazy. Try hard to figure these out before you look! It'll be a lot more satisfying.

There is a man who 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.
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?
A man is wearing black. Black shoes, socks, trousers, coat, gloves and ski mask. He is walking down a back street with all the street lamps off. A black car is coming towards him with its light off but somehow manages to stop in time. How did the driver see the man?
One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. How?
Why is it better to have round manhole covers than square ones? This is logical rather than lateral, but it is a good puzzle that 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.
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?
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?
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?
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 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.
A murderer is condemned to death. He has to choose between three rooms. The first is full of raging fires, the second is full of assassins with loaded guns, and the third is full of lions that haven't eaten in 3 years. Which room is safest for him?
A woman shoots her husband. Then she holds him under water for over 5 minutes. Finally, she hangs him. But 5 minutes later they both go out together and enjoy a wonderful dinner together. How can this be?
There are two plastic jugs filled with water. How could you put all of this water into a barrel, without using the jugs or any dividers, and still tell which water came from which jug?
What is black when you buy it, red when you use it, and gray when you throw it away?
Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday? (or day names in any other language)
This is an unusual paragraph. I'm curious how quickly you can find out what is so unusual about it. It looks so plain you would think nothing was wrong with it. In fact, nothing is wrong with it! It is unusual though. Study it, and think about it, but you still may not find anything odd. But if you work at it a bit, you might find out.

The solutions are below. Don't be lazy. Try hard to figure these out before you look!

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Solutions

The man is very, very short and can only reach halfway up the elevator buttons. However, if it is raining then he will have his umbrella with him and can press the higher buttons with it.
The surgeon was his mother.
It was day time.
At the time she went into labor, the mother of the twins was traveling by boat. The older twin, Terry, was born first early on March 1st. The boat 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.
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.
The poison in the punch came from the ice cubes. When the man drank the punch, the ice was fully frozen. Gradually it melted, poisoning the punch.
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. (Just what a HUMOR list needs!!) ;^)
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?
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. The is a simple puzzle to state but a difficult one to solve. It is a perfect example of a seemingly irrational and incongruous situation having a simple and complete explanation. Amazingly this classic puzzle seems to work in different cultures and languages.
The third. Lions that haven't eaten in three years are dead.
The woman was a photographer. She shot a picture of her husband, developed it, and hung it up to dry.
Freeze them first. Take them out of the jugs and put the ice in the barrel. You will be able to tell which water came from which jug.
The answer is Charcoal.
Sure you can: Yesterday, Today, and Tomorrow!
The letter "e," which is the most common letter in the English language, does not appear once in the long paragraph...

Alternate Solutions

Kyle Powerly offers several alternate solutions that fit and that are actually simpler, thus meeting Occam's Razor. (when presented with two explanations, the simpler of the two is probably the correct one)

Because one of them did not necessarily celebrate their birthday on the day they were born, but celebrated later or earlier. Much simpler than having Mom giving birth while crossing the International Date Line and tossing in a Leap Year and the like. Needlessly complicated.
Because he was the one who put the poison in the punch. Of course he wouldn't drink any *after* he poisoned it. Who goes to the effort of making poison ice cubes, except Bond villains and those bad guys in the "Encyclopedia Brown" mystery stories we read in elementary school?
Because they were adopted. It's a coincidence they were born on the same exact day. OK, so Occam's Razor could be applied equally to both solutions...