# Questions tagged [grid-deduction]

Puzzles such as Sudoku or Kakuro, where the final state of a pre-existing grid must be deduced logically through clues placed within and/or around the grid. For puzzles where you are given a list of clues which can be used to compose a grid to solve them logically, use the [logic-grid] tag instead.

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### My God, it's full of stars!

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids My dear friend, unknown to us, may have relocated again. He sent me imagery and constellation maps indicating that a distant red ...
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### Empty sudoku puzzle

The rules are the same as for a normal sudoku puzzle. The only thing different is that instead of numbers for clues, you have greater than/less than (> <) signs between the cells. Have fun solving!...
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### 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 ...
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### Happy Pi-Day! Try to solve this “PiDoku”

To celebrate the Pi-Day (3/14) adequately, a challenging math puzzle must not be missing. Rules: Fill in the numbers 1-9 exactly once in every row, column, and region. On top of that, you need to ...
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### Gerrymandering Puzzle - Rig the Election

The following graphic is a map of the country Mathlandia: You are currently running for reelection, but the polls aren't exactly in your favor. Each square in this grid is a county. Counties with a ...
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### R.H.P.C. crossword puzzle

This is an entry into the Fortnightly Topic Challenge #36 I got a ticket to the Red Herring Puzzle Club in the middle of the street. There was just a guy giving them out, like some advertisement ...
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### Desert Irrigation Project

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids My dear friend researches and designs canal irrigation systems in a remote desert. He's been missing for two weeks. Members of ...
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### The Ludicrous Loop: over a thousand cells of circular logic!

Flavourtext is for flavour only. Ladies and Gentlemen, are you feeling ludicrous today? A little loopy, perhaps? Then come one, come all, for I have just the thing for you. Lampreys and Jellyfish, ...
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### Japanese Fusion Alphabet Soup

The Dish... ...is an intriguing blend, with a base of classic Western flavours, and a twist of the Orient at its heart. The Ingredients... ...are diverse and are combined in such an unexpected - ...
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### One 'double agent' two-step on a waltzing floor

I'm in a jam – cornered I am! – No clue 'bout where to go Here's what went down, a pretty gown Some wine, a French chateau She whispered underneath her breath "Come dance with me and ...
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### Who am I??? Wait, isn't this a sudoku?

Jmw jrr qtlf tv ee M6SXr rro tr kz r tyr. Can you find out who I am? Hint 1: Hint 2:
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### Prime Number Snake

Place numbers 1 to 100 in the cells of the 10 x 10 board below in such a way that consecutive numbers occupy neighboring cells (either horizontally or vertically). Shaded cells should contain only ...
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### I am an island (ysaujdiolkiun)

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids I received an envelope containing two drawings and no return address. I would recognize that handwriting anywhere - my dear friend ...
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Solve five Slitherlinks, each with a unique solution. Please say a word regarding (or show an image depicting) each solution method.
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### Circuit Diagram

An entry to Fortnightly Topic Challenge #35: Restricted Title 1 - based on the following xkcd. Circuit diagrams can be quite difficult to understand, so here are some documents that will hopefully ...
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### GRID-THIRTY-SIX

Solve 36 puzzles (or more) to find the final 6 letter answer.
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### Introducing: Number Slope™

Number Slope™1 is an original2 grid deduction puzzle similar to Sudoku. It is solved on an n-by-n grid, tiled with n n-ominoes. The rules are: Each number from 1 to n must occur once and only once in ...
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### Sudoku embedded in a Kakuro

In addition to standard Kakuro rules, the grey shaded cells must form a valid Sudoku solution. One sum in this puzzle has been corrected from 28 to 23. Fortunately, it was in a location that nobody ...
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### The Determinant Sudoku

The determinants of $2\times 2$ matrices are calculated this way: $$\det\begin{bmatrix}a & b \\c & d \end{bmatrix}=ad-bc$$ And here's the sudoku-determinant puzzle: What's the solution for ...
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### WITLESS - A Puzzling Journey

IMPORTANT! READ ME: The only 'puzzle' parts of this are the links, titled 'Set X', 'Inscription X', or 'Constellation X'. Everything else is flavortext, apart from this readme section, although the ...
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### I've been everywhere, man

I am a knight facing a plight My dearest one of all Lives in a tower and won’t come out Unless her name I call I went to pick her up today And though my mind was set To do so, as I ...
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### Magic Maze Puzzle

Inspired by the board game, Magic Maze Set-up: Cut out each 4x4 tile, and the four small tokens (orange, yellow, green and purple), from the provided image below. Place tile 1 on a flat surface with ...
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### fill this grid with water!

In this puzzle you should fill the imaginary small squares in each row and column up to the number that is written next to it with water. You can't fill a square if the squares connected to it(under ...
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### A Six-Faced Puzzle

Here is a grid-deduction puzzle, whose mechanics I have seen under several names such as 'Castle Wall', which is the one I'll use here. The goal of Castle Wall is to draw a loop enclosing all the ...
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### Question 16 Ripple Effect

This is a Ripple Effect puzzle. The rules of this puzzle are: Fill in each region with numbers from 1 to n, where n is the region size. For instance, the top left region must have the numbers 1 to 5 ...
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### Parallelisation

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Puzzlers, I am presenting a set of six duo-grids! Of course, I need to tell you how they work - you are given a grid. Looking at it,...
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### Messages hidden in the “visit every square once” puzzle

I proposed my girlfriend yesterday, asking her to be my wife. but she did not answer me. Besides she gave me this 6 puzzles, below. She said I will know her answer after solving the puzzles. Inside ...
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### Pikurossword, or: Three-in-One

This is an entry into the Fortnightly Topic Challenge #36. [edit: i hope this wasn't too bad for my first puzzle here! let me know how i did :)] The answer to this puzzle should answer the question: ...
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### Making Things Difficult

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Factoring the Time Think fast! If you're looking for meaning, these clocks have some for you. Keyboards are Disgusting Gunky ...
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### Coloring a 4 by 4 grid

I made this simple puzzle a couple of years ago. There are three colors which appear in every row and every column. Moreover, every color appears 5 or 6 times in total. Find the color of the square ...
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### Oh no, it's another safe!

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Oh, did I feel proud after solving the last safe... until I was immediately dimension-doored (or something) into this room! Damn ...
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### Every Fourth Wormhole

An entry in Fortnightly Topic Challenge #33: Surface Geometry Mazes
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### You go wherever you go today

A conclusion to my entries in the Fortnightly Topic Challenge #32: Grid Deduction Hybrids. This metapuzzle incorporates the three previous puzzles in this series: Desert Irrigation Project I am an ...
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### Curiouser and Curiouser

CHAPTER ONE Alice was beginning to get very tired of sitting by her sister on the bank, and of having nothing to do: when she was overcome with the strangest sense of deja vu, and saw a 7x3 grid of ...
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### This new puzzle type needs a name {3}

I believe I have invented** a new type of puzzle... What is its name? ** Well, 'adapted' an existing one, really... Colour-blind-friendly version available here. Those without colour-blindness ...
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### HAISU (Room Count): An original grid-logic challenge

HAISU is a portmanteau of three Japanese words - 'hairu', to enter, 'su', number, and 'hausu', an English borrow word meaning house, of course. Together, we get a meaning of 'enter number house', ...
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### My Uncle's Music Box

Unfortunately, my favorite uncle just passed away. He's the one that taught me all about puzzling, and supposedly found Davey Jones' treasure in his youth. I miss him very much, however, I just ...
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### Popularity Within a Target Audience

This is a metapuzzle with four component puzzles and a final meta. Creations of CSIRO The Australian research institute CSIRO is notable for producing inventions such as gene shears, the insect ...
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### Another new puzzle type needs a name

For an example of how this type of puzzle works, see here... I believe I have invented another new type of puzzle... What is its name? Colour-blind-friendly version available here. Begin by ...
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### Stingray Nebula

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Inspired by the title of this xkcd comic, but in no way related or affiliated beyond the shared name. This is the stingray nebula: ...
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### Introducing: Compoundoku!

Rules of Compoundoku: Solve both left and right Sudokus. In addition, the board below them is the Compound Board of both Sudokus. Each number on the Compound Board should tell either: (1) ...
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### Slightly Odd Sudoku

Someone I find very trustworthy continues to insist that this is a valid Sudoku board. It's been a while since I've played, but surely there's a couple of things off here, right? Alright, so that ...
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### Untitled, for Now

As you step into the gallery, you notice an interesting piece of art hanging on the wall. "I like the piece, but what's with the title?" you ask the docent. "I'm used to obscure titles in modern art, ...
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### 3D nonogram, beginner's edition

Trying out the concept of 3D nonograms. This one should be pretty simple. Name the depicted object.
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### Help! Can you get my puzzle back?

Puzzling has a lot of really complicated stuff these days, so I just wanted to post a simple Boggle grid. You know that game, right? You form words by starting from one letter, then taking adjacent ...
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### Can you create a free-floating MASYU puzzle?

Rules of MASYU, for those unfamiliar: https://www.gmpuzzles.com/blog/masyu-rules-and-info/ Hey guys! So I just discovered this really cool puzzling site called the Puzzling Stack Exchange (puzzling....
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### Snakes on a Plane! 2

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Inspired by the title of this xkcd comic. Snakes ... on a plane ... again ... This time 2 specimens of a huge unknown type of snakes ...
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### Captain Pun's new boat

My good friend Captain Pun has bought a new boat. "And this is a picture of its sail!" he said, showing me this: "Solve the nonogram and you'll soon know what type of boat it is!" Can you solve ...