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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4
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2answers
196 views

Bullet Drop™ #1

Concept Here is a basic example grid: AB 1\/ 2\/ ×× The player must first modify the grid by switching the slashes \ and <...
8
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3answers
609 views

Getting all same side pairs

The goal is to get same side pairs of the 6 tiles, , to fit into a $2\times 3$ grid, so that all touching sides match like so (excluding the red part), for example:
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1answer
235 views

The Gardener's Route

Tell me the method for solving such grid problems in detail. I need a solution for The Gardener's problem.Tell me any method to construct the grid.
3
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1answer
118 views

Fill up the grid with the letters 'P', 'U', and 'Z' in the following way

Fill up the grid, , so that the letters '$P$', '$U$', and '$Z$' occur the same number of times both column-wise and row-wise, as well as diagonally for all diagonals with a number of cells that is a ...
14
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1answer
514 views

Why you shouldn't buy cheap puzzle books

Backstory contains important information, but nothing hidden. Also, tl;dr parts are bolded, but I can't guarantee I didn't forget bolding some part. Recently there's been a grid-deduction craze here ...
14
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5answers
1k views

A problem about Yin-Yang puzzles

In a Yin-Yang puzzle, one must fill every cell with either a black circle or a white circle according to the following rules: All cells with black circles form an edge-connected region. All cells ...
8
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1answer
183 views

4 More Meander Puzzles

My previous set of meander puzzles was fairly well-received, so I decided to make some more. If you didn't see the first set of meander puzzles, the instructions can be found here. Here they are: ...
27
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1answer
824 views

Every Fourth Wormhole

An entry in Fortnightly Topic Challenge #33: Surface Geometry Mazes
76
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2answers
3k views

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 ...
8
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1answer
277 views

Puzzles: Meander

I have come up with an interesting type of puzzle based on the mathematical concept of a meander. The concept, of course, is not original to me, but the type of puzzle is, as far as I know. A ...
15
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2answers
668 views

Tetromino Sudoku

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids The grid below, when filled in, forms a valid Sudoku grid. It can also be filled in like a LITS (nuruomino) puzzle without the 1x4 ...
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2answers
2k views

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 ...
27
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3answers
976 views

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 ...
51
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1answer
2k views

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, ...
52
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4answers
2k views

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 ...
30
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2answers
2k views

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,...
18
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2answers
605 views

Introducing: Jormungand

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Introducing: Jormungand A combination of Ouroboros (Slitherlink) and Numbersnake (Numbrix) to create the greatest snake-themed ...
18
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1answer
775 views

A Knight's Kuromasu

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids You are a knight in the king's army, and you've been tasked with constructing some walls. The problem is, as a knight, you are ...
2
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1answer
674 views

Move 2 or 3 spaces in this 5 by 5 grid

You have a 5 by 5 Board as shown. You start from the S (Center) position. You can: 1 Move TWO or THREE spaces only 2 You can move Vertically or Horizontally or Diagonally but only in a straight ...
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1answer
181 views

Arrangement at the puzzling class

PSE open a puzzling class. 16 students join the class. the classroom have 16 chairs arranged in (4 x 4) grid. ...
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3answers
3k views

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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1answer
538 views

Hexagonal Kurokuron

Kurokuron (クロクロ一ン: "black clone"), is a shading puzzle that first appeared in Puzzle Communication Nikoli issues 153-155. Identical rules apply to a hexagonal grid. Rules Shade some cells such that: ...
8
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2answers
1k views

Fill this 5x5 number grid incrementally, either by moving two boxes diagonally or moving three boxes in a row or column

One day, a friend has shown me a 5 by 5 grid, challenging me to fill it with numbers from 1 to 25. Obviously, it is not simple because there are some rules: The number 1 is placed in the center of ...
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1answer
2k views

Nested sudoku in entrance exam

My university set this question in 2013's entrance exam. Also the red boxes include from 1 to 9. What's the solution for this sudoku?
4
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1answer
803 views

Can you solve this kakuro puzzle?

This kakuro puzzle comes from the newest edition of Topple, an indie puzzle magazine I run. For those who are unfamiliar with kakuro, here are some instructions: Kakuro consists of a blank grid with ...
32
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3answers
3k views

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 ...
3
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2answers
469 views

36-length snake in a 6x6 grid

Based on https://brilliant.org/weekly-problems/2017-05-29/advanced/?p=4 We need to fill a 6x6 grid using the numbers 1-36, each cell having a single unique number, such that: Every two consecutive ...
5
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1answer
995 views

Difference square logic (5x5)

Rules : Arrange numbers 1 to 25 to the squares, and each number only occurs once. Green squares are the difference from its left square and its right square. Green squares are also the difference ...
14
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2answers
691 views

Trapezoids Compound Hidden Puzzle

UPDATE To refute Sconibulus's answer, I drafted a second puzzle with identical rules. 7 months ago, I released a collection of variations of an original puzzle called Trapezoids, but never mentioned ...
14
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2answers
497 views

Adderlink: Almost symmetrical

Rules: Hey, this looks like slitherlink! In fact, it is two slitherlinks added together. So both of the two slitherlinks have clues in exactly the same locations as this grid below. Furthermore, a 2 ...
16
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1answer
431 views

Karst - A variant of Cave

This is a variant of Cave applied to a 3.4.6.4; 3.42 6; 44 tiling. Rules Draw a single loop along the dashed lines that encloses some cells. Edges of this loop may not cross or share a ...
22
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1answer
1k views

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 ...
7
votes
1answer
399 views

Skeleton sudoku, the second

I've already set one skeleton Sudoku. Here's a rather harder one. (Nonetheless, it should be within the realms of what can be done by hand; I solved it manually myself to verify that there was only ...
8
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2answers
740 views

A spartan skeleton Sudoku

A skeleton crossword is a crossword where the black and white squares aren't given; you have to deduce them. Here's a generalisation of that idea to the Sudoku puzzle. Here's a 4 by 4 grid, with four ...
6
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1answer
303 views

My featured entry

Mosaic is a Minesweeper-like puzzle based on a grid with a pixel-art picture hidden inside. Using logic alone, the solver determines which squares are painted and which should remain empty until the ...
6
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1answer
430 views

ASCII Art Painting

I've been taking an art course recently, and I met someone who was proficient with grid ASCII art paintings. However, the teacher of the class always seemed to think there was something wrong with his ...
18
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2answers
2k views

Who can spot the difference?

My family and I have just moved house! Lucky us! So what did my family do? We held a housewarming party, and rung everyone in the neighbourhood up to invite them. So, anyway, people were coming in ...
8
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3answers
533 views

Ambiguous Grids

After six to eight weeks of waiting, your Shmikoli™ Ambiguous Grid Deduction Puzzle Set has finally arrived! You tear into the box only to discover that the instructions are missing. You shouldn't ...
10
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1answer
520 views

Oriental House: An original grid-deduction challenge

A different approach to an old concept of mine, Oriental House is a new grid-deduction puzzle based once again off exits and entries. The rules are as follows: Draw a path from S to F, passing ...
9
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1answer
1k views

What is a “unique solution” in a Slitherlink puzzle?

In the question Five Slitherlinks, the querent suggests that "each [Slitherlink puzzle has] a complete solution". I'm newly reading about Slitherlinks, but I don't understand what makes a solution "...
39
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4answers
2k views

Five Slitherlinks

Solve five Slitherlinks, each with a unique solution. Please say a word regarding (or show an image depicting) each solution method.
12
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5answers
2k views

Move the coin in the color grid

You need to move the Coin from the S(tart) cell to the END cell. Rules: From S you can move to cells 2,7 or 8. From BLUE cells you can only move ONE space diagonally. From YELLOW cells you can only ...
17
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1answer
1k views

Sudoku with only 8 predefined numbers

Have fun with my self-made Sudoku puzzle. Solve this Sudoku puzzle using the standard Sudoku rules: Fill any row, column and bold-framed area with the numbers 1 to 9. Hint: It is not as difficult as ...
6
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2answers
553 views

Cairo pentagonal tiling logic grid (Edit : with more clues)

Rules : Fill with numbers from 1 to 13, and each number can appear max 4 times. Small numbers between 2 cell shows the difference between the cells. A + D = B + C Example : (In this example, I fill ...
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1answer
652 views

Solve the Mosaic

Mosaic is a Minesweeper-like puzzle based on a grid with a pixel-art picture hidden inside. Using logic alone, the solver determines which squares are painted and which should remain empty until the ...
34
votes
6answers
1k views

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 ...
9
votes
1answer
969 views

Logic 5x5 Letter Number Combination Grid

Hey I just thought other might enjoy the challenge of this puzzle as much as I did. Not the most easy thing to solve. Sort of like Sudoku, each row and column needs the letters A,B,C,D,E and each row ...
12
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1answer
403 views

Is it Pajamas? Or Shampoo? Maybe a Cheetah? Oh I know, it's:

Title hint:
18
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2answers
1k views

Three for the price of one

While browsing through your local puzzle store, you see something you can't resist: a box which promises two grid deduction puzzles for the price of one! The vendor explains that the box contains a ...
26
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4answers
1k views

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 ...