Note: I have invented this puzzle myself as far as I know. I'm certainly not aware of having read it anywhere else. I have no idea whether it will be hard or easy.

A man is imprisoned in a strong steel cage with a steel floor. The cage is open at the top but the vertical bars are greased and cunningly designed and no matter how hard he tries he will never be able to escape that way. He has no access to tools nor anything he can make tools from. Every day he has access to adequate food, water, bedding and toilet facilities (Edit: Plus shelter from the elements), but none of these can be used to break out of his prison.

Outside the cell is another similar cell that encloses it. It has no facilities. Outside that is a yet larger cell enclosing that one. It has no facilities. This goes on like Russian dolls for some time.

The man can see the outside world through all the bars. He knows that if he can escape from the cages he will be released.

The guard throws him a key-ring with keys to all the doors of all the cages and departs back to the guardhouse. The man desperately wants to escape.

Instead he stays in the inner cage for a long time before leaving. Later he ventures into the next cage but soon returns to the inner cage and stays there for a long time. Then he ventures to the next cage but returns once more to the inner cage. He repeats this as many times as there are cages.

Finally he walks free and never returns to the cages again. On the way out he takes out his wallet and pays the guard a substantial amount of money. He is safe and free for the rest of his life.

What is going on?


The man and the guard are the only two people (or creatures) involved in the situation but there was a mobile crane in use just before the above story starts. It also leaves before the story starts. However the crane was not used to lift any part of the cages or other equipment and was not used to help the man escape in any way.


The cages are plainly built with unclimbable bars and are roughly square-shaped. Each has a single door. If the cages weren't there, the man could easily walk to the guardhouse in a couple of minutes.

There is nothing designed to frighten or hurt the man about the setup.

EDIT to address questions in the comments.

@Display name - This is describing a real man in a real situation. Whether it will ever happen in real life is debatable but it just might.

@CR241 - The man is not wrestling. He is alone in the cages the whole time.

@Displayname - The cages do not reach all the way to the guard house. They are fairly close in size with a relatively small gap in between. It would have been more sensible of me to make them square but all of the same height. I just didn't think of that. The height just needs to be enough for them to be unclimbable.

@fakedad - You ask if the geometry of the cages is important. On thinking about it, I've added that tag. So yes. However he can't climb or break out and the only exit to each cage is its door. That is why he needed the keys.

@Hugh - Having looked at the definition of the story tag, I don't think it comes under that category. Clearly there is a story involved but I'd say this is more of a situation. I'll look into this further though.

@JimM - The locks and keys are well-maintained and are just normal ones that open easily with no special tricks or time-limits. The man can open or lock them at will.

@Steve V. - As long as the man is constrained to leave by the doors and can't break or bend or damage anything it doesn't matter what the cages are made of.

  • $\begingroup$ Is this an actual man in a situation that may happen in real life? I would hate for the answer to be that the man represents some fictional character (or worse, something that's not even alive), or that the man represents a board game piece. $\endgroup$ – Display name Dec 15 '18 at 0:04
  • $\begingroup$ Would the story tag fit this? $\endgroup$ – anon_user Dec 15 '18 at 0:49
  • $\begingroup$ It seems like professional wrestling going on in the steel Cage.. WWE (World Wrestling Entertainment).. Is it kind of punished to that man or what? $\endgroup$ – CR241 Dec 15 '18 at 0:56
  • $\begingroup$ @Displayname - a 15 minute walk is pretty far, and the cages are roughly cubic which would imply the bars of the outermost cage are ridiculously tall... this doesn't sound like a structure that can exist in real life :-) $\endgroup$ – deep thought Dec 15 '18 at 2:10
  • 1
    $\begingroup$ Are the doors identical, or near enough that makes no difference? $\endgroup$ – Tom Dec 15 '18 at 15:25

12 Answers 12


One beneficial but rather mean possibility is that:

The man is oversized, and he needs to lose weight to squeeze through the inner door. However the next door has a slightly smaller gap, and he needs to retreat to his base for some time, to lose more weight to squeeze though the second door. And so on, each door becoming smaller, until eventually he has lost enough weight to exit the last door.
The guard may have been employed by the man to lose weight and paid on success. The keys were given to the man as his goal was to slim, and if the guard had the keys, the man could command him to free him (using the crane), but as the man had the keys he had to lose weight.

  • $\begingroup$ Accepted! I'll give the complete answer as I imagined it in an answer of my own. Would you like to hazard a guess as to why the guard is called a guard? And why there were keys that were given to the man? $\endgroup$ – chasly - supports Monica Dec 15 '18 at 15:33
  • $\begingroup$ Oops, the question has been closed. I don't know why but at least you have answered correctly so let's leave things as they are. :-) $\endgroup$ – chasly - supports Monica Dec 15 '18 at 15:59
  • 6
    $\begingroup$ Closed as too broad - apt considering the man's predicament :P $\endgroup$ – Tom Dec 15 '18 at 16:06
  • $\begingroup$ Nice one, haha! $\endgroup$ – chasly - supports Monica Dec 15 '18 at 16:07

This looks like

He's in a zoo of some kind. There are some kind of predators in every next cage, which would be happy to meet him (but the feeling is not mutual). They are distracted periodically (for example, for feeding) but will rush back to him while he's fiddling with the next lock. So he has to open one door, wait for the animals to get distracted, open the next door, rush back to take shelter in his original cage, wait, repeat.

  • 1
    $\begingroup$ Ingenious but the only two people or creatures necessary for the story are the man and the guard. Not the answer I am looking for. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 9:26

This feels a bit underconstrained, but one possible solution is:

The locks are on a timer, only opening several hours after the key is used (or only at a certain time of day/week). The reason the man returns to the center cage every time is that the outer cages have no facilities and thus the central cage is the most comfortable place to wait while waiting for the the next lock to be openable.

  • $\begingroup$ This is getting close but the locks don't have any fancy mechanism. They are just plain locks. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 9:25

This is

some kind of escape room. The man has voluntarily put himself in there, but is refused to leave before he can figure out how by himself. He indeed has all the keys, but has to figure out how to use them, probably by some clues in the inner cage

He pays the guard a large amount of money because

the guard is the owner of the escape room, and charges by the hour. This is also why he is desperate to leave. He thought it would be easy, but now it just costs him a fortune

  • $\begingroup$ This is getting very warm. It has a lot of the correct elements.However he doesn't need to go back to the inner cage for the reason you suggest. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 9:54


There are guards who patrol the area in shifts, and the prisoner does not want to risk being caught, so he only tries to unlock one cage in between shift rotations.

  • $\begingroup$ Ingenious but not the answer I am looking for. :-) There only needs to be one guard. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 9:55

My immediate thoughts relate to my own interests, and are not terribly general.

The man is in a shark cage. The bars of the cage go above the surface of the water, so he cannot climb out. His air source is also in that cage. So when he leaves the inner cage and takes time to unlock the next level of the cage, he must return to get his air. After the thrilling experience, he pays the operator (whose role was to guard the man's safety while he was in the cage, not to guard the world against the man).

Or, similarly:

The man is undergoing hyperbaric treatment. At each stage of treatment the pressure is raised to the original depth, then brought up a bit to decompress, then brought to the original depth, then brought up a bit more, and so on. The man's health is the key to progressing his treatment, and he has it soon after being admitted. After the treatment completes, he is free to go but must pay the doctor/guard.

  • $\begingroup$ This definitely has some of the right elements. However the cages are on land. Remember he can walk to the guardhouse. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 11:03

The area between each cage and the next one is

mined, or otherwise dangerous to stay in for a long period. But there's a delay on the trigger.

  • The man leaves the innermost cage and enters the second one, thus

    triggering the mines or other danger in that region to be activated. He then returns to the innermost cage while they blow, and ventures out again when that area is safe once more.

  • After this, he can move through the first two cages into the third one,

    triggering the mines there. Again he returns to the first cage (furthest from the danger) until it's safe to go out again.

  • This process continues $n$ times until

    all the areas are safe and he can walk all the way out.

I can't at the moment see any reason why this shouldn't be valid - it seems to fit all the requirements given in the question. (As a side note, the pattern of moves taken by the man somehow reminds me of the algorithm for solving the Tower of Hanoi.)

  • $\begingroup$ I can see the strength of your argument. I should have thought to say that there is no danger present in any of the cages or any extra equipment other than what I have mentioned in the main question or the clue.. So it isn't the scenario I was thinking of. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 13:06

The bars forming cells-within-cells make up a maze. The prisoner was lowered into the maze using the crane (which then departed) and spent his imprisonment mapping the maze on the floor of the cell as best as he could, using the supplies (soap, toilet items) he has available. Since his perspective from any one location is limited, and since the map is inconvenient or impossible to redraw, he needs to return to the cell each time to update it with the new information he gains by moving from cell to cell. It takes a while because new supplies are only provided at set intervals and he needs to consume most of them to survive.

  • $\begingroup$ Interesting. You are correct about the use of the c***e that you mention at the beginning of your second sentence! It is worth thinking about this. However because there are bars on all the cages, he can always see the extent of the next cage without having to leave the previous one. In any case he could just walk around the perimeter until he finds the door which is visible from any angle. The supplies are freely available $\endgroup$ – chasly - supports Monica Dec 15 '18 at 13:54

Every time a door is opened, some a big amount of money is appears in the innermost cell, maybe as a mechanism to bait the prisoner back to cage while the guard has time to lock the door again. In this case the guard was corrupt and had a deal with the prisoner to share the money if he let him out.

  • 1
    $\begingroup$ Not the answer I am looking for. The man has his wallet with him the whole time and has a constant amount of money. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 11:18

This man has been stuck in this cage for all his life. He has always been taken care of here. He has always been wondering what the outside world is like. When he gets thrown the keys and has the chance to escape, the "fear of the unknown" kicks in and he cowers in his inner cage. After some time he collects the courage to open his cage and enter the next one, but fear quickly overtakes him, after which he cowers back to his safe place: the inner cage. This goes on for some time till he finally frees himself.

About the money

The money has been his only useless object in his inner cage. As this man has never seen the outside world, he never had any idea what to do with the money. It has become an artifact of some sort to him. As he wants to express gratitude to the guard for the keys, he hands this "useless artifact" to the guard, as a way to say "Thank you".

  • $\begingroup$ Ingenious but not the answer I am looking for. He was only in there for a short while before being given the keys. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 9:54

The key ring is the kind where you have to slide the key around to take it on or off (it doesn't snap open). When the guard threw the man the keys, the key ring landed on one of the bars. Since the man can't climb the bars, he has to take the keys off of the ring. To keep them in order, he takes them off and puts them back one at a time until he finds the one that opens the inner cage. Then he takes the keys one at a time to open each cage until he gets to the outermost one.

But this doesn't explain

why he had a wallet and it doesn't use the fact that he gave the guard money.


Cognitive Behavioral Therapy for...

...claustrophobia The person in question is claustrophobic, and they want to be cured of it. Their physician suggested they try Cognitive Behavioral Therapy. The person is locked in but can at any time escape the cage when the strain gets too much. Once locked in they desperately want to escape because the phobia compels them to, but they steel themselves not to, even though they have the keys.

  • $\begingroup$ Hmm... interesting but why the guard under your scenario? However, this isn't the solution I'm looking for. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 12:10
  • $\begingroup$ @chaslyfromUK To monitor the patient's state so that they do not go into some kind of catatonic or psychotic or other such state during which they can no longer make an informed conscious decision about the continuation of treatment. Also I must point out that this kind of open-ended question where many things can fit and we as answerers have no way of telling whether we have hit upon the "right" answer is not a very good riddle. Any riddle where an answer can get the response "Ok, that answer fits everything in the riddle, but it is wrong", is a poor one. $\endgroup$ – MichaelK Dec 15 '18 at 12:16
  • $\begingroup$ I understand your point. I think the problem is that there is no way I could limit a situation type question without pages and pages of conditions that exclude every possible other answer. Most importantly, the community can judge your answer to be a good or bad one and mark you accordingly, regardless of my opinion. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 12:24
  • $\begingroup$ @chaslyfromUK Well that is exactly why I think the riddle is bad, because you only gave a little bit of what is required to his upon the answer. It is kind of like saying "x + y = 10. What is x and y?". And when someone says "Well, x could be 3 and y could be 7" and you say "well, true, but that is not the answer I am looking for". $\endgroup$ – MichaelK Dec 15 '18 at 12:31
  • $\begingroup$ That is true but then the community would quite rightly recognise your answer as correct. They would surely mark you up and and probably mark me down. This is the first question of this type that I have attempted so I'm learning from this experience and will try to make my next one more well-defined. $\endgroup$ – chasly - supports Monica Dec 15 '18 at 12:43

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