# All Questions

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5 views

### I invited them and no one came

My colleague told me this morning with frustration: To 200 friends I sent invitations to my birthday party, and not one person came. The last paragraph of the invitation had a mysterious sentence ...
34 views

### Number of turns for two wheels to bring edge-points together

The puzzle is as follows: We present you below this riddle. A certain mechanism opens a gate of a maximum security lab. It just happens that a glass lets you see the mechanism and you know the ...
48 views

### I need some help with this 15x15 nonogram [closed]

I have been working on this nonogram for some time and can't seen to figure out what to do next...
52 views

### Can anyone think of more examples of pair of words like “Mindful” and “Mind full”? Both sound same and have different/opposite meanings [closed]

I am looking for pair of words or using multiple words which sounds similar but have different/opposite meanings(like an example mentioned in the question above). I posted this question in English....
37 views

### How to solve this quiz question on monty hall problem? [closed]

I need help with this question Imagine that you're in a game show and your host shows you three doors. Behind one of them is a shiny car and behind the others are goats. You pick one of the doors and ...
66 views

### The Alan Parrish question

Two stereotypical british gentlemen that don't know each other engage in this unusual conversation (it's almost as if they were a setup for a puzzle): Gentleman A - Hello sir, I'll have you know that ...
113 views

### The Green Periodic Puzzle

This puzzle follows from the Purple Periodic Puzzle (these puzzles are solved individually). Another strange periodic table has appeared and it's hiding a secret word. Can you find out what's strange ...
52 views

### Fair and square island hopping [duplicate]

If amateur fiction is not your thing skip to the bottom. As IP (Implausible Physics) expert for DREAM, the Department for Reckless Engineering and Advanced Megalomania you have been tasked by sheikh ...
319 views

### Calculation - the hard way

This is a puzzle I love to play with my math students and I hope you will enjoy it too: You are given the numbers 1, 2, 3, 4, and 5 exactly once. Your target is a number, e.g. 36. Can you create a ...
88 views

### A Peculiar Find-A-Word

I was solving a crossword in my local newspaper when I came across a clue that made no sense: 19 Across: Be inappropriate On the face of it, there is nothing odd with this clue until I realised: 19 ...
1k views

### 28 Minutes Later

An entry in Fortnightly Topic Challenge #50: Escape Rooms I open my eyes to find myself lying in a bed in a white room. Sitting up is difficult, as a tangle of wires and tubes are attached to my arms ...
174 views

### Peas at the barbecue saved the day!

You were at your neighborhood barbeque when noticed a lady reporting a theft to the police. This is what you heard: Lady: Help! A man grabbed my purse and ran away! Police: Did you notice anything ...
453 views

### The Purple Periodic Puzzle

Below is a periodic table that's hiding a secret word. Can you find out what's strange about this purple periodic table and find the answer. Text-only version: ...
40 views

### How to find a zip file as large as possible [closed]

How one can find a text file with 1000 bytes which zip file is as large as possible? I think it must be over 1000 bytes.
60 views

### Finding the hypotenuse of a right angle triangle when one side has been given [closed]

If one side of a right angle triangle has length equal to $a^{n-1}$, where $n\ge2$ and $a$ is any odd number greater than 1, how do we find the length of the hypotenuse? The lengths of the sides of ...
46 views

### Decrypting a block cipher puzzle from a hex string [closed]

I have the following hex-string puzzle: ...
2k views

### How many matchsticks need to be removed so there are no equilateral triangles?

The puzzle is as follows [with minor copy edits for grammar]: By only using matchsticks of equal length a set of equilateral triangles has been built as indicated in the figure from below. With that ...
207 views

### How to get the least possible sum in a closed loop set of squares?

The puzzle is as follows: The figure from below represents a set of 12 squares joined forming a closed loop. By using only the numbers from 1 to 12 fill in the blanks. The condition is that, without ...
136 views

### How many lines are needed to connect all smiling toasters in a 4x4 grid?

The puzzle is as follows: How many straight lines do you need to draw the least possible to join all the smiling toasters if you should not raise the pen or go over any line already drawn? Remember ...
315 views

### Two knight tours on a 4x4 grid

Two knights are placed on opposite corners of a 4x4 grid. Can you move* each knight 7 times, such that each cell of the grid is visited exactly once by exactly one of the knights? *Note that a knight ...
215 views

### Minimize the longest King chain on a 6x6 ternary grid

This puzzle is an extension of this one: Minimize the longest King chain on a 5x5 binary board Given a grid filled with numbers, we define a King chain to be a path on the grid such that: The path ...
118 views

### Minimize the longest King chain on a 7x7 binary grid

This puzzle is an extension of this one: Minimize the longest King chain on a 5x5 binary board Given a grid filled with numbers, we define a King chain to be a path on the grid such that: The path ...
398 views

### Sometimes with Feathers?

When in red, I was very loud. In high definition, a treasure. You put me in to interfere. Rest on me for your leisure. Put me between the last two letters, I am an Asian plant. Keep some of me in the ...
59 views

### intercepting the box [duplicate]

If you need to send a message in a box to a person so that no one can intercept it and get the message, how do you do so if you have a padlock and key and they have a padlock and key
79 views

### Vowelburger™ Inside-Out Burger

Inspired by Avi's Vowelburger™ Riddle here and Ébe Isaac's Double Supreme Riddle. The local Vowelburgers™ has added a new item to their ever-expanding menu, the Inside-Out Burger! This peculiar ...
183 views

### Choosing squares on a square board [closed]

I have an $8 \times 8$ board. On the board, I want to choose 2 unit squares in each column and row such that none of the chosen squares are touching. This means they cannot share a side or a corner. ...
225 views

### An Evil Cartesian Psycho

I came up with this puzzle when I was in high school. There is an island owned by an evil man who keeps some tourists who were visiting the island a few years ago captive. The authorities demanded ...
945 views

### Working as a Family

Within this Boggle grid are the names of the members of a family. The unused letters will reveal the name of the original head honcho. ...
128 views

### Chess - I will eat!

Suppose that you are playing White, and your aim is to eat a black piece (pawns qualitfy) in the fewest moves as possible and Black are not cooperating at all, and, even more, Black's aim is to ...
2k views

### A Math Riddle: But the math does not add up

Grandpa had a lot of different books of stamps on his desk. He was counting them. I was curious. “What are all those stamps Grandpa?” “I just got back from the Post Office son and bought a bunch of ...
193 views

### These words have the same properties, but how?

Asparagus, Man, Erode, Aerodynamic, Innards, Bins Mine, Rob, Fort, Hexagon, Tera, Nights Flashbacks, Lost, Mono, Grand, Dystopia, Focus Splashdown, Troupe, Karate, Duel, Catchy, Contact Acrobat, ...
219 views

### All possible locations of a robot going from $(x,y)$ to $(x+y, y)$ or $(x,x+y)$ [closed]

Suppose I had a little robot on the coordinate grid that moves according to the following rule. If it's at the point $(x,y)$, it can move to either $(x+y,y)$ or $(x,x+y)$. If the robot starts at the ...
386 views

### The Pub Quiz and the Passion

An entry in Fortnightly Topic Challenge #49: Pub Quiz Camouflage...a day or two late. Oops. Your local pub has an interesting way to show their pub quiz questions--sixteen televisions in a four-by-...
120 views

I like rebuses, here are four of them. 1. 2. 3. 4. Good luck!
78 views

### Reverse Engineer Chess Software Calculations

TLDR Just the Puzzle Given a number n and a weight w the function f will result in a weighted number r as follows. f(n, w) = r n can be a number from 0 to 200 w can be a number from -100 to 100 (...
125 views

### Solving the equation $A^4=B^4+C^4$ [closed]

Let's have the following numbers: $2\sqrt7$, $\sqrt{\frac{7\sqrt{674}-168}{2}}$, $3\sqrt7$, $-\sqrt{\frac{7\sqrt{674}-168}{2}}$, $2\sqrt7$ Can you put these numbers into three different groups A,B,C ...
103 views

These words can be sorted into four categories, each of which share a connection. driver soldier bowl monolith megawatt infinite wing Sweden descends skin blazes legendary herself rocks grand prix ...
247 views

### What type of puzzle is “Room to Grow”?

I saw this game on Steam that's not yet released. They have a demonstration of the game in video form here, and here's the GIF I generated from that video (that's lower in quality and shortened due to ...
228 views

### I unlocked an item!

I came up to someone and they gave me some clues: It's fast, but can't run. It gets me ready for life. Everyone can have it. It is sold everywhere. It was here since Day 1. So I went to find it, and ...
105 views

### We see it in our everyday lives!

I just realized that I kept on finding something wherever I go. In my bathroom, my fridge, the map, outside, with the clouds. I see it everywhere! Can you tell what it is? H1:
95 views

### The Author of a Note

After finding this note, I've pretty much gone to the ends of the earth to find the author's name. Maybe you can help me? Suppose I want my room to be a weird color. Something uncommon, like purple. ...
1k views

### A Pub Quiz Joke

An entry in Fortnightly Topic Challenge #49: Pub Quiz Camouflage For this pub quiz, I urge you to listen closely. The final word hidden within this pub quiz describes, jokingly, what pub quiz ...
110 views

### “Friend”-ly Puzzle

All stories in this puzzle are fictions; the puzzle was made by myself. My friend left me a puzzle. He gave me 5 papers, each had some information on it. #1 WORD SEARCH A B C D E F 1 SOR SUF HYP ...
61 views

### Identifying series of numbers in the pizzle [closed]

I'm trying to solve this puzzle and couldn't come up with a reasonable solution ? 4 2 5 ? 9 6 12 ? I couldn't figure out what ? is..
84 views

### Dividing the first 10 numbers into two groups with similar product

Can you paint all numbers from 2 to 10 with red and blue colour, such that the product of all red numbers is as close as possible to the product of all blue numbers?
187 views

### Nurikabe: The Terrible Tower of Threes!

This puzzle is a quick and fun little Nurikabe that is very tall, because I am not. It's not particularly tough, but if you need a nice relaxing grid-deduction puzzle to calm your brain today, this ...
162 views

### The Burnt Textbook

You and your team have successfully intercepted a message from the enemy, which could win you the war! But the message is encrypted with a difficult cipher, and your textbook's instructions for ...
182 views

### Which piano piece is played here?

The picture shows a typical pattern of a piano piece. Which piano piece is played here? Hint1: