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14
votes
2answers
982 views

(1 of 11: Numberlink) What is Pyramid Cult's Favorite Activity?

Dear PSE users and moderators, I’m new here in PSE, but I really need your help. There was this person who gave me a black envelope consisting 10+1 pages of puzzles, and also a scribble saying: “Find ...
15
votes
4answers
38k views

Is it possible to use one sequence of moves to solve the Rubik's cube from any position?

Is there a sequence of moves that can be repeated over and over again which can solve any legal position the Rubik's Cube? If so what is it, and if there's more than one, what's the shortest? If not, ...
18
votes
3answers
3k views

Knights and jokers

There are $N$ men. $K$ of them are knights, $M$ of them are jokers. $N$ is known, $K$ and $M$ are unknown. You know that: $K + M = N$, $K \gt M$, $M \ge 1$, $N$ is odd. Knights always tell the truth, ...
16
votes
5answers
2k views

Cards in the darkness

A man is sitting in a dark room. In front of him is a pile of 100 cards. He knows that there are 90 cards faced up and 10 cards faced down. Is it possible for the man to form two piles from these ...
10
votes
4answers
10k views

N balls and a scale

The question of twelve balls and a scale is probably the best-known example of the "find the ball of a different weight" problem. But does it generalize? Is there a general way to find a weighing ...
30
votes
3answers
2k views

Fun with Flags part 1: something different

We are looking for 4 categories. Other (independently solvable) puzzles of this type: 2, 3, 4, 5, 6, 7, 8, 9, 10.
20
votes
3answers
2k views

Twelve Labours - #03 Golden Hind

This puzzle is part of the ‘Twelve Labours’ series. Previous instalments can be found here: Prologue | 01 | 02 Hercules was grateful the morning sun wasn’t hotter as he pulled the heavy flatbed ...
13
votes
4answers
1k views

Nerds, Jocks, and Lockers

Here's an oldie but goodie from The Daily WTF; I paraphrase to avoid copyright issues: A middle school math teacher, who also happened to be the P.E. coach, made the following deal with the non-...
22
votes
4answers
3k views

The Monty Hall problem

I'm amazed that, although well known, this problem hasn't been posted yet. Monty Hall You are on a game show. The host of the show shows you three doors. He tells you that behind one of them, is a ...
22
votes
4answers
3k views

I am an expression of a deer mint - Clue One

You wake up one morning, and immediately look over at the letter on your bedside table. It reads: Dear [redacted]: You have been chosen to assemble the most powerful thing in the world - the [...
20
votes
2answers
4k views

Alphabet splitting extraordinaire!

Here are three ways of splitting the letters of the English alphabet into two groups: 1) ABDOPQR; CEFGHIJKLMNSTUVWXYZ 2) BCDGJOPQRSU; AEFHIKLMNTVWXYZ 3) DFHIJLNOPRTUVXYZ; ABCEGKMQSW In each case, ...
10
votes
6answers
606 views

Find the value of $\bigstar$: Puzzle 1 - Evaluation

This puzzle replaces all numbers with other symbols. Your job, as the title suggests, is to find what number fits in the place of $\bigstar$. All symbols abide to the following rules: Each symbol ...
5
votes
5answers
4k views

A Set of Water Jug Challenges

You've probably heard about challenges with water jugs, so why not try a few? Use 3- and 5- liter jugs to get 4 liters. Use 5- and 7- liter jugs to get 4 liters. This one's different. How many ...
40
votes
7answers
8k views

Guide to Codes and Ciphers

Note: This is a Guide not a Puzzle ciphers are quite common now on puzzling, and at first can seem quite confusing. But ciphers are bigger than this site, used worldwide by companies and secret ...
121
votes
13answers
21k 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 ...
59
votes
5answers
9k views

How to beat Count Dracula

Abraham Van Helsing and Jonathan Harker play a game against Count Dracula. The three players agree on the following rules: Count Dracula and Van Helsing enter the crypt, while Jonathan Harker ...
34
votes
3answers
5k views

Pirates and gold coins

A group of N pirates has come by a chest containing 200 gold coins. Their rules require that the coins be distributed by the following approach. The pirates are ranked from fiercest to meekest and ...
47
votes
11answers
284k views

6, the magic number

Here's a fun (albeit difficult) one: Make these equations true using arithmetic operations: ...
43
votes
5answers
30k views

A five card trick - How does it work?

At a party last night, my friends Alice and Bob did a magic trick. Any ideas how it worked? Alice shuffled a pack of cards, and asked me to take five. I looked at them. She put the rest of the pack ...
35
votes
1answer
7k views

Coins on a table

John and Jane are playing a game. They both go to the bank and get 1000 euros in 2 euros. So each of them has 500 euros at stake. They then find a large rectangle table and decide who wins the ...
20
votes
1answer
1k views

Community Metapuzzle - The Broken Time Machine

(This is the community metapuzzle, discussed in this meta thread. It requires answers from nine other puzzles linked below.) You find a mysterious device sitting on the ground. It's labelled in a ...
25
votes
5answers
2k views

Polyomino T hexomino and rectangle packing into rectangle

Let's pack some (one or more) T hexominoes together with some (one or more) small $a\times b$ rectangles into some bigger $m\times n$ rectangle without holes and overlapping pieces. For example, I ...
25
votes
4answers
854 views

Recycling old answers

Each of the puzzles below gives a two-word answer. Solve the puzzles and arrange the resulting 16 words into four groups of four, each with a common theme. The resulting group names form a clue for ...
19
votes
1answer
467 views

Fun with Flags part 7: attention please

We are looking for an idiom. Hint 1: Hint 2: Other (independently solvable) puzzles of this type: 1, 2, 3, 4, 5, 6, 8, 9, 10.
17
votes
4answers
16k views

Drawing something using one pen stroke

Can you determine if it's possible to draw a geometric figure (made up from shapes like rectangles, triangles, and other regular shapes) with one pen stroke and not drawing the same line twice. I am ...
17
votes
2answers
415 views

Fun with Flags part 4: a pile of coasters

These quaint looking coasters appear to have been thrown haphazardly on the table. However, there is a 10-letter word to be found, which is the answer to this puzzle. Other (independently solvable) ...
16
votes
2answers
2k views

Knights and knaves in a foreign language

You die and ascend to heaven, there is a knight (truth-teller), a knave (pure liar) and a joker (random) sitting on a cloud - they all look the same. In order to gain entry you must determine their ...
14
votes
6answers
3k views

Use 2 0 1 and 8 to make 67

Use $2$ $0$ $1 $ and $8$ to make the number $67$ RULES You must use all 4 digits. Only the digits 2, 0, 1, and 8 can be used. You can make multi-digit numbers out of the numbers. Examples: 20, 82, ...
13
votes
2answers
640 views

Fun with Flags part 6: left right left

We are looking for the name of a country leader. Other puzzles of this type: 1, 2, 3, 4, 5, 7, 8, 9, 10.
13
votes
1answer
2k views

The Security to the Party [Part 2]

A party is being held at a local mansion. The host is very rich and his success is because of one thing ~ his famous recipe for Spaghetti! The only guests that may attend are people who correctly ...
12
votes
2answers
410 views

Fun with Flags part 9: a different design

We are looking for a 3-word phenomenon. Hint 1: Hint 2: Hint 3: Hint 4: Other (independently solvable) puzzles of this type: 1, 2, 3, 4, 5, 6, 7, 8, 10.
9
votes
2answers
844 views

Twelve Labours - #04 Erymanthian Bar

This puzzle is part of the ‘Twelve Labours’ series. Previous instalments can be found here: Prologue | 01 | 02 | 03 Now one crate lighter, Hercules made his way back up the road to the Erymanthian ...
6
votes
3answers
378 views

Find the value of $\bigstar$: Puzzle 2 - Switch-a-roo

This puzzle replaces all numbers with other symbols. Your job, as the title suggests, is to find what number fits in the place of $\bigstar$. All symbols abide to the following rules: Each symbol ...
29
votes
2answers
2k views

Fun with Flags part 2: a musical connection

We are looking for a song (artist and title). Other (independently solvable) puzzles of this type: 1, 3, 4, 5, 6, 7, 8, 9, 10.
24
votes
1answer
591 views

Fun with Flags part 8: it's your roll

We are looking for a 12-letter word. Other (independently solvable) puzzles of this type: 1, 2, 3, 4, 5, 6, 7, 9, 10.
17
votes
1answer
246 views

Fun with Flags part 10: don't lose count

In a Formula 1 race, the chequered flag was waved so violently that the black and white patches got mixed up. Who was waving the flag, when and where? Other (independently solvable) puzzles of this ...
16
votes
3answers
718 views

Fun with Flags part 3: what used to be

We are looking for 4 countries/kingdoms/sovereign states which do not exist anymore. Hint: Other (independently solvable) puzzles of this type: 1, 2, 4, 5, 6, 7, 8, 9, 10.
14
votes
1answer
853 views

Heyacrazy: Crosses

This is a Heyacrazy puzzle. Heyacrazy is an original genre, inspired by the "two border" rule of Heyawake and Heyawacky. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells ...
12
votes
4answers
1k views

Fun with Flags part 5: with a smile

We are looking for a song (artist and title). Other (independently solvable) puzzles of this type: 1, 2, 3, 4, 6, 7, 8, 9, 10.
9
votes
1answer
373 views

Gladys's Clashing Cryptic

Dear Puzzling, Remember me? I have some exciting news for you. I'm starting on a new journey to visit a few wonderful landmarks around the world. In case you want to follow my travels, I'll send you a ...
6
votes
7answers
4k views

rescue operation - where is your partner?

Your partner's space ship has crashed on an uninhabited planet. Only the radio transmitter and his compass were still in operation. He asks you to rescue him, and tells you how to find him by the ...
407
votes
4answers
35k 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'...
56
votes
3answers
252k views

What is the number of the parking spot?

One needs to find the number under the car.
52
votes
3answers
6k views

Sliding Bolt Puzzle

You are in a room with two adjacent doors locked by four sliding bolts. The bolts are movable and block only one door at a time; however, you do not know which bolt currently is blocking which door. ...
26
votes
4answers
8k views

How do you solve a word puzzle when you have no idea where to start?

When you're looking at a logical word puzzle, what sorts of clues should you try to look for to solve them? There have been quite a few puzzles posted to this site so far that I spent a few minutes ...
25
votes
3answers
7k views

The lake monster

You are on a rowboat in the middle of a large, perfectly circular lake. On the perimeter of the lake is a monster who wants to eat you, but fortunately, he can't swim. He can run (along the perimeter)...
36
votes
4answers
15k views

How many chess pieces does it take to “cover” all spaces on a chessboard?

Given an 8x8 chessboard, your goal is to "cover" each space on the board with the fewest possible number of pieces. A space is "covered" if there is a piece on it, or if a piece on the board can be ...
14
votes
1answer
7k views

Fastest way to cross a river: four people with different rowing speeds

This problem is commonly cited as a Microsoft interview problem, although I have paraphrased it here to involve a river and a boat instead of a bridge and a flashlight, and tweaked the crossing times ...
10
votes
3answers
1k views

See me once, see me twice

A very short riddle just came to my mind, let's see if it can be cracked: see me once, food can usually be found see me twice, thundering typhoons all around hints are coming daily, if needed. ...
21
votes
1answer
1k views

Statue Park: Knight's Lines

This is a Statue Park puzzle. Rules of Statue Park: Shade some cells of the grid to form the given set of pieces. Pieces may be rotated or reflected. Pieces cannot be orthogonally adjacent (though ...

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