All Questions
26,867
questions
566
votes
5
answers
69k
views
A short, brutal riddle
Left alone, I'm a word with five letters.
I'm honest and fair, I'll admit.
Rearranged, I'm of no use to trains.
Again, and I'm an overt place, warm and well lit.
What am I?
- 9,733
440
votes
4
answers
42k
views
This is important. I need you to listen…
Look, you don't know me. We've never met. But, like I said, I need you to listen...
I had the most disturbing dream the other night... Woke up in a cold sweat and couldn't get back to sleep. It wasn'...
- 37.1k
339
votes
1
answer
16k
views
A puzzle in 140 characters
Your final answer will respond to the question "Why don't I like Twitter that much?"
Like usual, I'll confirm any sub-answers if you find them
Here's the link to the puzzle on Twitter.
Here's the ...
- 10.5k
268
votes
1
answer
30k
views
Is this Tetris puzzle solvable?
As a birthday present last year, I received some fridge magnets. They didn't come as a puzzle, so I don't know if they have a solution, but I made a puzzle out of them anyway.
The magnets are ...
- 4,573
263
votes
6
answers
24k
views
241
votes
8
answers
28k
views
My prefix is food, my suffix is rude
I thought of this riddle myself. Feedback is appreciated.
My prefix is food.
My suffix is rude.
My infix comes in rounds.
I keep you off the ground.
What am I?
- 14.4k
218
votes
1
answer
14k
views
An overheard gang meeting, a double agent, and a murder
I was walking home late last night and heard raised voices coming from a boarded up old warehouse. I stopped, out of sight, to listen...
[When I started eavesdropping, the conversation was already ...
- 37.1k
213
votes
1
answer
29k
views
Lock your computer when you walk away!
Well this is strange.
I forgot to lock my monitor when I walked away from my desk, at work, and one of my co-workers decided to have a little fun.
When I got back, I found this little C# console ...
- 8,432
200
votes
10
answers
22k
views
Game of Life: Kill the Sun
Below is an initial state for Conway's Game of Life with a single pulsar. Living cells are white.
The area marked with red is your base. You are free to modify any of the red cells, but only those, ...
- 5,667
195
votes
26
answers
95k
views
In the 100 blue eyes problem - why is the oracle necessary?
The riddle
Randall Munroe (of xkcd fame) has, a bit hidden on his site, a logic puzzle:
A group of people with assorted eye colors live on an island. They are
all perfect logicians -- if a ...
- 2,270
183
votes
3
answers
9k
views
Deusovi Honeypot
Looks like the community has spoken.
With a heavy heart (as if), I have trapped @Deusovi behind a never repeating, fractally recursive, infinite, unsolvable labyrinth. To keep him busy, I added a ...
- 75.8k
179
votes
1
answer
11k
views
Chaos and Order: a visual puzzle in stained glass
I created a visual puzzle, which my wife then implemented as part of a stained-glass window. I've no idea if it is (a) obvious, (b) stupid or hopefully (c) extremely clever, and hence would love to ...
- 2,023
172
votes
1
answer
10k
views
Merlin and Hermes: Mysterious Lines
Two adventurers, Merlin and Hermes, approached a large iron door built into a cliff face."Well...", said Hermes, "What do we do now?". Merlin produced an old, large piece of crumpled paper from his ...
- 14k
172
votes
1
answer
14k
views
Internship Available!* - Figure out what you're being asked to do before you sign up
Sine waves bound in rectangles shaped into prisms. Mass increases, position changes twice, and mass decreases. The prisms become rectangles and are either discarded or stored for later use. If that ...
- 3,845
167
votes
1
answer
6k
views
The Rube Wordberg Machine
Gah! I used to be the brilliant one at Verba Retorta University, but ever since that damned Professor Wordberg showed up, there's been nothing but trouble. And it's all his confounded machine's fault!
...
- 37.1k
155
votes
4
answers
11k
views
Find the letters that complete these five patterns
Complete the last line in each of the following five series:
Puzzle 1:
"Using" is E
"Desist" is I
"Visits" is E
"Design" is ???
Puzzle 2:
...
- 5,123
150
votes
12
answers
22k
views
A double-agent with a conundrum
You are a double-agent in the most important war of the 20th century, The
Falklands war. For years you have been playing the United Kingdom and Argentinian
governments against each other, taking ...
- 1,859
145
votes
2
answers
10k
views
A mysterious email from Andrew Void
You are a secret agent in the service of the KGB, about to embark on a highly dangerous mission to infiltrate MI6. You have your disguise, your papers, and your backstory all prepared. The night ...
- 116k
142
votes
8
answers
45k
views
How can 64 = 65?
Here is a interesting picture with two arrangements of four shapes.
How can they make a different area with the same shapes?
- 1,906
141
votes
2
answers
8k
views
Hearken, now, and listen close!
Hearken, now, and listen close; I have so much to tell.
Now lend an ear and do your job; you surely will excel.
To find my hidden message, gaze on every word herein.
While skimming through it ...
- 25.7k
135
votes
7
answers
52k
views
Mensa IQ test question - lines in squares
Which of the 8 tiles below is missing?
I've been trying to figure out the answer to this question for quite some time. Can anyone spot the pattern?
Source: https://www.bergmandata.com
- 1,459
135
votes
13
answers
24k
views
This is it. This is the one. Find your wife
If you have found her, maybe you could try saving her?
You come home one day and find your wife is out. You open your computer and discover an email from her.
To xxxxx,
/
Curiosity killed the ...
- 56.4k
133
votes
8
answers
24k
views
The Sheikh dies
The Sheikh dies, leaving behind three sons, 17 camels and the following order:
His oldest son shall inherit one in two camels.
His middle son shall inherit one in three camels.
His youngest son shall ...
- 2,433
129
votes
16
answers
1.6m
views
Two doors with two guards - one lies, one tells the truth
You are a prisoner in a room with 2 doors and 2 guards. One of the doors will guide you to freedom and behind the other is a hangman–you don't know which is which, but the guards do know.
One of the ...
- 5,718
129
votes
1
answer
9k
views
How can this shape perfectly cover a cube?
The following shape:
can be folded onto the surface of a cube in a way that perfectly covers the entire cube with no gaps and no overlaps.
How can this be done?
- 5,580
127
votes
12
answers
29k
views
Paying the Troll toll
You are on your way to visit your Grandma, who lives at the end of the valley. It's her birthday, and you want to give her the cakes you've made.
Between your house and her house, you have to cross 7 ...
- 2,204
127
votes
2
answers
14k
views
Which country is INDIA in?
An intrepid globetrotter needs to know this:
BENIN is in Libya
CANADA is in China
DENMARK is in the United States
FRANCE is in Germany
INDIA is in ??
- 70.4k
126
votes
5
answers
141k
views
Is this duplo train track under too much tension?
My kids were making this train track of duplo the other day, and this is what they put together. They are still very young, and for them, this is something big. They were really proud that they ...
- 4,834
125
votes
1
answer
7k
views
124
votes
2
answers
7k
views
⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀ ⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀ ⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀...
- 13k
123
votes
7
answers
29k
views
100 Prisoners' Names in Boxes
Names in Boxes
The names of 100 prisoners are placed in 100 wooden boxes, one name to a box, and the boxes are lined up on a table in a room.
One by one, the prisoners are led into the room; each may ...
- 1,987
121
votes
1
answer
4k
views
Paper Picture Puzzle
Here is a puzzle I drew
Your final answer will be what you need to know to solve this puzzle (You'll know it when you have the final answer)
Notes:
I did a couple dumbs. One is the space planning. ...
- 10.5k
119
votes
13
answers
15k
views
If you only have half of me, then I am of no use
People think a part of me is sticky, but I'm not. I do have a
sticky friend though.
I can create almost anything, but I'm not very creative.
After I have done my thing, you can't tell ...
- 1,977
117
votes
8
answers
7k
views
Make all the statements true
Can you make all the below statements true with a single click? If yes, explain how.
Three + Eleven = Ten
Seven + Five = Six
Two + Four = Eight
NB: 'A Single Click' means, with only a single left ...
- 14.5k
114
votes
5
answers
16k
views
Mate in 0 moves
Not exactly a traditional chess puzzle, and I won't offer much of an explanation for fear of giving away the answer.
White must mate in 0 moves, meaning he must deliver a check mate without touching ...
- 3,667
114
votes
3
answers
11k
views
Prove that π > 3
It seems that once upon a time some politicians tried to pass a law fixing the value of π to be exactly 3. The idea being to "make math simpler so that our children can get better at math".
...
- 26.8k
114
votes
2
answers
56k
views
3 Logicians Walk Into a Bar
Three logicians walk into a bar. The barman says, 'Does everybody want a drink?'
The first logician says, 'I don't know.'
The second logician says, 'I don't know.'
What does the third logician say?
...
- 4,253
114
votes
9
answers
16k
views
A hunt for long forgotten treasure ...but beware the pirate's curse!
I never really knew my uncle growing up. He seemed nice enough, but I got the sense from the distant, troubled look in his eyes that there was at least some truth to the rumours...
Years before I was ...
- 37.1k
109
votes
1
answer
19k
views
Cryptic Clue Guide
This post is not a puzzle. There is nothing puzzly hidden inside it or the self-answer, posted at the same time.
What exactly is a cryptic crossword clue, and how do I write one?
- 145k
109
votes
3
answers
8k
views
The brain-curdling eldritch horrors and the third dimension
We're in the year 2016 so it's finally time to take puzzles to the 3rd dimension!
So let's see what those beautiful times bring us today:
(click to enlarge)
Everyone of you clever sods could as ...
- 3,010
109
votes
1
answer
7k
views
This party ends in tragedy (I planned it from the start, you see)
The DJ from Moscow was pumping out tunes.
The house mostly bare but for furniture, strewn;
A sofa for three and an armchair for one.
The guests started piling in, looking for fun...
'Twas ...
- 37.1k
106
votes
9
answers
21k
views
Five coloured doors, which leads to freedom?
You have been incarcerated in a high-security prison for several nefarious crimes which we need not go into here. The warden, being a kindly logician, offers you a single chance to escape. You are ...
- 116k
106
votes
1
answer
7k
views
A strange hotel
Entering the lobby, I requested a room. The clerk handed me my key and I took the elevator to my floor. To my surprise there was a sign on the door of my room telling me I should try a different room ...
- 1,701
105
votes
15
answers
41k
views
My wife has died
In 1980, a man lives on the 30th floor of his building. Every morning he wakes up, gets ready, kisses his wife, takes the elevator down to the first floor, and goes to work.
One morning, he wakes ...
- 11.7k
105
votes
4
answers
8k
views
Checkmate in 1 on a Tangled Board
Lots of pieces are tangled here.
Can you find mate in one?
Small hint to guide you in the right way:
- 2,625
105
votes
2
answers
7k
views
This new puzzle type needs a name
I believe I have invented a new type of puzzle...
What is its name?
Colour-blind-friendly version available here.
Begin by solving the 16x16 sudoku; each of the digits 1-16 must appear exactly ...
- 133k
98
votes
3
answers
10k
views
Do I Work with an Orangutan?
This morning I found myself face-down in front of a large building. It was obvious that I had taken a great fall from one of the rooms above me, but now I apparently had amnesia.
I went in.
I could ...
- 25.6k
94
votes
7
answers
25k
views
Why does this solution guarantee that the prince knocks on the right door to find the princess?
I found this puzzle online:
On the top floor of a castle lives a princess. The floor has 17 bedrooms arranged in a row. Each bedroom has doors connecting to the adjoining bedrooms as well as to the ...
- 2,393
93
votes
4
answers
16k
views
It's my birthday today - how old am I turning?
It is my birthday today
Last year I had 5 candles
4 were lit the last was not
But today, I'll light them all
How old am I turning today?
HINT: I am not turning 5 today and...
- 791
93
votes
9
answers
14k
views
Coin Flipping Game with the Devil
You die, and awake in Hell. Satan awaits you, and has prepared a curious game. He has arranged $n$ quarters in a line, going in the east/west direction. He placed the coins at the ends tails up, and ...
- 32.1k