Newest Questions
29,037 questions
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Belated best wishes 2025 - four empty suguru (tectonic) puzzles - can you solve this using logic (without backtracking algorithm?)
I've become totally addicted to tectonics and in specific empty tectonics. Came across the tradition (see: 2024 2023) to generate four empty tectonics in the form of the digits of the year.
I couldn't ...
19
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3
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Can you get all the coins no matter where they are placed?
I have placed a dime in nine of the 36 squares of a 6x6 grid. All coins are visible.
You may choose three rows and three columns and take all the coins you find in them. You can look at the grid and ...
- 27.6k
-4
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1
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179
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Two-by-two grids of integers: which number replaces the question mark? [closed]
Here is my own puzzle: two squares are filled with numbers, another square contains numbers and question mark.
Which integer number replaces the question mark and why?
The ? has to replaced with a ...
- 1,364
5
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1
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374
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Riddle Written on 10 Stones
I saw the same 10 st𝗼𝗻𝗲s, writ𝘁𝗲𝗻 below:
Call = 1
Web = 2
Harmonic Analysis = 4
Heaviness = 8
Hear = ?
What are they standing for, and what is the value of “Hear”?
- 2,712
11
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1
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278
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Connoisseur cryptic crossword
Solve on Penpa+
Across
1. Dubious quality? So be it, in dubious quality (15)
9. Extremists in Éire's congress forming kingdom on nearby island (5)
10. Ten to the eighteenth and ten into each (3)
11. ...
- 83.7k
6
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1
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226
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Simple word search
The 37 listed words are hidden below, can you find them all?
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- 3,801
4
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1
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Crossword and Affix Riddle
Partial answers are fine, but the check mark goes to the solver of the affix riddle.
Clues
(Note: # of letters in parentheses does not include spaces)
Across
20 U.S. state with the longest ...
- 20.1k
5
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4
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603
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πthagoras cycloid angle
See:
https://www.geogebra.org/classic/arvz3m7d
where you have black slider to draw a blue cycloid by running the yellow-cyan circle with radius $1$ from distance $0$ to distance $2 \pi$.
The green ...
- 2,192
8
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1
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The answer is fabulous!
This is part 7, see for part 6: The answer is a highly composite number
The answer is fabulous!
2nd
2nd
4rd
4rd
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3rd
- 12.7k
3
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1
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128
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origami: t2 unsolvable? cube net
The objective is to fold the shape into a rectangle with uniform thickness 2. There are no restrictions on how many folds you can make, how long each fold can be, where the fold can be, et cetera.
In ...
- 3,072
7
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1
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207
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Min-Max Circuit Deduction
Handmade Puzzle: Min Max Circuit
Fit in the numbers satisfying the following rules.
Each row and column should contain 1~9 distinctly.
- Maximum cell: This cell should contain bigger number than ...
- 2,712
0
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2
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168
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4x4x4 cube with no 4 monocoloured cubes in a straight line
This is based on this great question.
Can you construct a 4x4x4 cube with 16 red, 16 green, 16 blue and 16 yellow cubes, such that there are no 4 cubes of a single colour in a straight line?
- 38.7k
0
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0
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How do I reassemble a Rubik's Cube? [duplicate]
Disassembled my Magic Cube and I put it back together thinking it was the right way. Now every single time I try to solve it normally (I know how to solve Rubik's Cubes) there's always something wrong....
8
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1
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578
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1
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1
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175
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Fill a partially completed 5x5 Latin square with diverse diagonals
Beginner puzzle (suitable for people who are new to puzzle solving).
To allow new users to solve this puzzle and earn reputation points, I encourage all users whose reputation is 200 or more to not ...
- 27.6k