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17
votes
1answer
751 views

See me once, see me twice #2

I had a lot of fun with my "see me once, see me twice" question, so I thought I'd make a series out of them. So here is the next riddle: see me once, the hammer falls. see me twice, the gamer ...
13
votes
1answer
315 views

Follow the path of relation through the grid #1

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
24
votes
1answer
887 views

I make billions

I make billions, I never spend less than $1000, I'm a man in black, I'm a force of nature, I'm the original, Audiences of all ages have seen me. Who / what am I?
10
votes
1answer
762 views

Twelve Labours - #05 Eugene's Tables

This puzzle is part of the ‘Twelve Labours’ series, but can be solved independently. Previous instalments can be found here: Prologue | 01 | 02 | 03 | 04 After being snookered by Pholus’ puzzle for ...
8
votes
4answers
308 views

Find the value of $\bigstar$: Puzzle 3 - Substitution

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 by the following rules: Each symbol ...
8
votes
5answers
1k views

Polyomino Z pentomino and rectangle packing into rectangle

See my similar question about T hexomino (Polyomino T hexomino and rectangle packing into rectangle) This is exactly same but with other polyomino - Z pentomino. Let's pack some (one or more) Z ...
7
votes
1answer
297 views

A Range of Rebuses

In the Land of Rebuses, I found some paper, as well as a few images: Some of these have already been tackled here: 1 2 3 4 Any images were found on freesvg.org or drawn manually. The answers to ...
3
votes
1answer
7k views

How can I switch 2 yellow corners that are on the same face from a 3x3 cube?

How can I switch there two corners?
41
votes
3answers
8k views

The coolest checkerboard magic trick

In the small town of Terni (Italy), there's a couple of young friends named Marco and Leonardo, who like to perform magic tricks to a restricted audience of common friends and relatives. They like to ...
61
votes
19answers
9k views

Growing anagrams - What is the longest possible list forming a sentence?

This is a challenge for word-puzzle lovers. It might be a bit more of a game than a puzzle, but I think it is not limitless in it's answers, so a final answer could be found (eventually). What is the ...
22
votes
4answers
44k views

How do I solve the world's hardest sudoku?

This question is posted under the guidelines Don't worry too hard about restricting or regulating anything that isn't turning into a problem yet. If you don't agree that this question is on topic, ...
32
votes
6answers
145k views

Clever ways to solve Mastermind?

Is there any specific way to solve Mastermind? Apart from the first step that is pure chance, is there any way to continue based on the colors that you think are correct?
12
votes
3answers
870 views

How does one go about creating a new grid-deduction puzzle?

The grid-deduction tag covers puzzles like Sudoku, Kakuro, etc. where the goal is to fill in a grid of numbers [/letters/colours] in a unique way by logical deduction from some predetermined rules and ...
22
votes
4answers
2k views

Treasure hunt 'round the world! (prologue)

It's here. Finally here. For weeks you've waited, checking the mail every single day, to no avail - but today, your invitation has finally arrived. You eagerly tear open the envelope and read: ...
54
votes
4answers
54k views

What is the largest tile possible in 2048?

I can get to 4096 max. There are videos on youtube of guys making it to 8192. What is the theoretical maximum limit on this? PS: if you haven't played this, here is the link to addiction.
4
votes
1answer
402 views

Number sequences: 6X000X9, 700XX08,00000015,?,00000015

Here is the question: 6X000X9,700XX08,00000015,?,00000015,?,00000015 This question actually comes from the puzzles made by my friend. He gave me his puzzles recently but I couldn't figure it out. ...
17
votes
11answers
12k views

Knight, Knave and Joker puzzle

Here is an excellent puzzle with 3 types of characters: You are lost in a town and meet 3 men. You somehow (God told you) know that they are Knight, Knave and Joker. Knight always tells truth, ...
12
votes
1answer
2k views

I, for one, welcome our new

An entry in Fortnightly Topic Challenge #30: Metapuzzles... For two months, the ship had hovered above the world ... silent, unmoving, just relentlessly hovering in a fixed spot over a desolate ...
26
votes
2answers
4k views

What's the password?

War has broken out in the kingdom. The king's castle is guarded pretty heavily, by guards with instructions to kill anyone who can't produce the correct password. Unbeknownst to the guards, the ...
14
votes
1answer
404 views

Twelve Labours - #06 Stymphalian Beards

This puzzle is part of the ‘Twelve Labours’ series, but can be solved independently. Previous instalments can be found here: Prologue | 01 | 02 | 03 | 04 | 05 Hercules looked down at his to-do list ...
12
votes
1answer
3k views

Burning ropes as timers - How many time intervals can be measured?

Note: This is a follow-up question to Burning ropes as timers. The following question and its answers may contain spoilers. To sum up the puzzle, these are the rules (slightly modified): You have ...
9
votes
8answers
2k views

Four Directions - Where and what am I?

To the North I see headstones, but to my surprise - no grass, no dirt, and no clay. To the South is the smallest you probably can't visit, then nothing for a very long way. To the West is a garden ...
16
votes
4answers
14k views

Fast strategies for solving Einstein's puzzles?

The Einstein's puzzle or zebra puzzle is a well-known logic puzzle. Are there any very easy ways to solve it fast?
14
votes
2answers
631 views

Ooohh, it all makes sense now! :D

Introduction As requested by @Rubio, I am here to state that this is a metapuzzle based on other puzzles listed below. "Ooohh, it all makes sense now! :D" ~ Mr Pie The Puzzle Or does it? Answer is ...
12
votes
1answer
402 views

I make billions (#2)

I make billions (#2) At 9, I met my best friend, At 12, I lived an outdoor life, At 13, I broke my arm right before camp, At 15, I worked my first corporate job, At 17, I was ...
11
votes
3answers
3k views

Simple twisting riddle

One of the riddles we used to have painted on the walls of one of our classrooms in secondary school (with the last part added in :+ ): What runs but doesn't walk, has a mouth yet still can't ...
10
votes
4answers
56k views

Swap the edges in a solved Rubik's cube

I have a rubik cube, which always have two swapped edges in the last layer. No matter which color I start with, there are always two edges in the last layer which remained swapped with each other. ...
6
votes
3answers
330 views

Tiling rectangles with X pentomino plus rectangles

Inspired by Polyomino Z pentomino and rectangle packing into rectangle Also in this series: Tiling rectangles with F pentomino plus rectangles Tiling rectangles with N pentomino plus rectangles ...
3
votes
2answers
244 views

Connect Wall V. S. Word Web

This post is a question about puzzles, not a puzzle in itself. There is nothing puzzly hidden inside it or the self-answer, posted at the same time. No lateral thinking is required. Question 1: What ...
-2
votes
2answers
344 views

Shortest number of attempts to solve this issue [duplicate]

There are 9 identical balls but only one of them has a higher weight. You are also given a weight balance. How many attempts would you require to identify the ball with the extra weight and how?
12
votes
3answers
913 views

Input/Output Problem #1

The basis for this problem is that you did to make an optimal pattern so that all inputted sequences will be "accepted" if they fit the rules of the problem and "rejected" if they break any of them. ...
12
votes
1answer
582 views

Piece de Resistance - Six-six-six. An Ultimate Wall of Cryptics

Six - six-six. An Ultimate Wall of Cryptics This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five Six ... Aha! This one is of ...
11
votes
1answer
2k views

Of men and hats

There's an obvious generalization of this problem: There are a rather large number of prisoners, each of them seeing the color of the hat of all the following sad fellows bot not their; the hats may ...
8
votes
1answer
472 views

A Sincere Nurikabe Puzzle

So here's a standard Nurikabe puzzle. I'll be using the final (solved) grid for my upcoming local puzzle competition logo as it will spell the abbreviation of the competition name. So, what does it ...
7
votes
1answer
231 views

Follow the path of relation through the grid #2

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
6
votes
2answers
216 views

Find the value of $\bigstar$: Puzzle 4 - In Between

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 ...
6
votes
1answer
200 views

Follow the path of relation through the grid #3

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
5
votes
1answer
274 views

Tiling rectangles with Hexomino plus rectangle #1

Inspired by Polyomino T hexomino and rectangle packing into rectangle See also series Tiling rectangles with F pentomino plus rectangles and Tiling rectangles with Hexomino plus rectangle #1 Next ...
3
votes
2answers
2k views

Make numbers 93 using the digits 2, 0, 1, 8

I have a 1 to 100 building challenge with 2, 0, 1, 8, all made but 93 is not made. I need your help! This is similar to the "Four fours" puzzle, but using the digits 2, 0, 1 and 8. Rules: Use all ...
71
votes
12answers
12k views

Turn off all lights in a ring-shaped palace

Not a very difficult question, but one I enjoyed nonetheless and wanted to share with the community. You are a servant in a palace. The palace is in the shape of a circle, and you do not know how ...
78
votes
11answers
22k views

Correct way to add 22 to 4 to get 82

Inspired by this other puzzle, tell me a correct way by which adding 22 to 4 will give 82. As in that other puzzle, these numbers are all expressed in base 10.
155
votes
3answers
7k 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 ...
43
votes
9answers
22k views

The Longest Word Made from Chemical Symbols [closed]

So, as you probably know, each and every element in the Periodic Table has its own unique chemical symbol, which is either one, two, or three letters long. For instance, Oxygen is represented as O and ...
94
votes
2answers
5k 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 ...
26
votes
5answers
3k views

What are the features of a well-written puzzle?

When making a new puzzle, the average person is usually faced with a hard problem of guaranteeing quality. I want to know some key points and ideas, for beginners and experts alike, to keep in mind ...
46
votes
10answers
173k views

1 2 3 4 5 6 7 8 9 = 100

The sequence of numbers $1\ 2\ 3\ 4\ 5\ 6\ 7\ 8\ 9$ has the property that you can insert mathematical operators in between the numbers from $1$ to $9$ and make the expression evaluate to 100. For ...
21
votes
4answers
5k views

Hidden in plain sight - By what method do these images hide a prime number?

Note: This question has been severely edited from its original version to better fit the format of this site. Some answers below - including the accepted, correct answer - have been given based on the ...
16
votes
3answers
24k views

What's the fewest weights you need to balance any weight from 1 to 40 pounds?

Suppose you want to create a set of weights so that any object with an integer weight from 1 to 40 pounds can be balanced on a two-sided scale by placing a certain combination of these weights onto ...
32
votes
18answers
49k views

Draw a line through all doors

I saw the following problem on 4chan and couldn't solve it: It's very likely to be some kind of troll (no solution). I'm hoping to see some rigorous proofs that disprove the existence of such a line....
21
votes
3answers
6k views

N pirates steal their share of bananas to the benefit of a monkey

The following is a type of logic / math puzzle I've yet to see on this site. I feel it belongs because the kernel of this problem can be reworked into other puzzles. $N$ pirates find themselves ...

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