Questions tagged [no-computers]

A puzzle designed to be solved without using calculators, online decoders, or computer programming. Using a computer to type and post the answer is allowed; the spirit of this tag is to make people solve the puzzle on their own.

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7 votes
1 answer
389 views

What Language Is This?

It is the year 2204, and we have finally found intelligent extraterrestrial life. We are delighted about this, so we asked the aliens, ...
HelloWorld's user avatar
6 votes
0 answers
201 views

Mate-in-25 tsumeshogi

This is apparently the first shogi-related question on this site! Yay! Anyway, this is a mate-in-25 tsumeshogi. Sente (the player with the pieces pointing up) is to move and by an uninterrupted series ...
Parcly Taxel's user avatar
  • 7,251
19 votes
1 answer
896 views

Anyone Seen My Snorkel?

This is part 54 of the puzzle series Around the World in Many Days. Each part is solvable on its own. mqoı ugw7qж , zqv qw o h6ım v6ınɔ ugwo7 | zo 78վn £þxm εıqm conxnøqxw v8կox h6ımw , დnɔ þn 7დvn ...
Jafe's user avatar
  • 77.7k
9 votes
1 answer
588 views

Hardcore Lighting - Excalidraw

Each yellow cell is a light that shines in exactly one direction, horizontally, vertically, or diagonally, endlessly, and goes through any block as long as the block is not a wall. Black cells do not ...
Sny Smartie's user avatar
  • 2,264
-6 votes
1 answer
147 views

Why does the grid look different?

Relatively easy puzzle: Why does the grid look different?
Sny Smartie's user avatar
  • 2,264
4 votes
1 answer
503 views

Surely it's not Sny again

Each dot is a light, which shines in exactly one direction, horizontally, vertically, or diagonally (like a bishop, in a 45-degree angle). Lights shine through each other. Uncover the secret message ...
Sny Smartie's user avatar
  • 2,264
3 votes
1 answer
268 views

7 Lights in 7 Tetrominos

In each orange tetromino, place a light that shines in all directions horizontally and vertically. Light shines through tetrominoes. Tetromino tiles are considered unlit initially and may be lit. ...
Sny Smartie's user avatar
  • 2,264
6 votes
2 answers
184 views

River crossing cats and dogs

A farmer and his $n$ cats and $m$ dogs are on one side of a river. There is a boat that can carry the farmer and at most $k$ animals at once. The boat doesn't move without a person operating it. The ...
Bubbler's user avatar
  • 12.2k
6 votes
5 answers
3k views

Math is Awesome

I have a shirt. It says that $AWE+SOME=MATH.$ A, W, E, S, O, T, M, and H are not necessarily distinct positive integers from $0$ to $9$. The goal is to find the maximum possible value of $MATH.$ If ...
Ronchen Luo's user avatar
6 votes
2 answers
425 views

Pawns and a chessboard with no three aligned

This little problem crossed my mind and appeared to be not quite trivial. How can you place P pawns on a chessboard with the constraint that no pawn is exactly midway between two other pawns? Sure ...
Florian F's user avatar
  • 28.2k
3 votes
0 answers
84 views

Another hand tiling puzzle - 8 convex shapes from 7 polyiamonds

Arrange the 7 polyiamonds in the image into 8 different convex shapes. One after the other, not simultaneously... Rotating and flipping allowed. No gaps or overlaps. Should be a fairly easy puzzle.
theonetruepath's user avatar
3 votes
0 answers
125 views

Hand tiling polyiamond puzzle. Non-trivial

Group these 30 polyiamonds into five sets of six, then use each set of six to make five different convex shapes. There are some repeated polyiamonds, no set of six may contain a duplicate. The convex ...
theonetruepath's user avatar
2 votes
1 answer
250 views

Constructing 2024 from the first 7 natural numbers

Can you use each number 1, 2, 3, 4, 5, 6, 7 exactly once, the four operations +, -, *, / and the parentheses to construct the number 2024? Bonus: can you find multiple distinct solutions? No computers ...
Dmitry Kamenetsky's user avatar
-1 votes
1 answer
223 views

First five digits of a googol factorial

Based off of: MacPOW 1134 Without using a calculator/computer, can you determine the first five digits of $10^{100}!$ (a googol factorial)? I came up with this when trying to solve the question this ...
CrSb0001's user avatar
  • 1,622
2 votes
0 answers
118 views

Make three different convex shapes with four polyiamonds, by hand. Five times

To while away the endless holidays. Start with the four polyiamonds in row one. Arrange them without gaps or overlaps (flipping/rotating allowed) in a convex shape. Repeat for two more convex shapes, ...
theonetruepath's user avatar
6 votes
1 answer
432 views

Where are your kids?

You are a mom (or dad) with two boys, Stephen and Philip, aged 8 and 10. While you have been out in the garage, they have been in their separate rooms doing their homework before being allowed to play....
Stevish's user avatar
  • 1,335
11 votes
1 answer
403 views

Best Wishes for 2024: Four empty Suguru (Tectonic) puzzles

To continue last year's tradition, hereby four empty suguru puzzles. Rules of suguru: Each square gets a number so that each block of n squares has the numbers 1..n, and neighbouring squares (...
Kris Van Bael's user avatar
10 votes
2 answers
639 views

It ended with an AFTERSHOCK

I started with a single-letter English language word. At each step, I added a letter of my choice, then re-arranged the letters to make a new word. I ended up with: AFTERSHOCK How did I get there? ...
pmacfarlane's user avatar
6 votes
1 answer
340 views

Add as few plus signs as possible to make equation true

To allow new users to solve this puzzle and earn reputation points, I encourage all users whose reputation is 200 or more to not post an answer until 48 hours after this question is posted. Thank you! ...
Will Octagon Gibson's user avatar
18 votes
2 answers
762 views

PSE Advent Calendar 2023 (Day 9): The Peppermint Twist

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2023. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > This puzzle ...
Jeremy Dover's user avatar
  • 27.4k
2 votes
2 answers
337 views

First digit of a large number

Can you find the first digit of $2^{2^{2^{2^{2^2}}}}$? Basically, it is $2$ to the $2$ to the $65536$ power. You cannot use a computer, but are allowed to use a calculator. Good luck!
A Math guy's user avatar
5 votes
1 answer
140 views

Ended up with 'empathise'

I started off with a one-letter English language word. For every step, I added one letter of my choice, and re-arranged the letters to make a new word. By the end, I had: EMPATHISE What was the word ...
pmacfarlane's user avatar
0 votes
1 answer
83 views

Minimum function optimization puzzle #4: Using negative numbers?

Previous puzzle Take this puzzle of mine that I created around a week ago: Take these 3 functions: $f(x):=x+8,g(x):=x^2-3,h(x):=\sqrt x$ Starting from $x=0$,$$\color{black}{\text{How many times will ...
CrSb0001's user avatar
  • 1,622
0 votes
2 answers
135 views

Minimum function optimization puzzle #3: 3 functions

Previous puzzle Take this puzzle of mine I created recently: Let $f(x)=x+1$, $g(x)=x^2-1$, $h(x)=2x-4$. Starting with $x=0$ and applying these functions as needed, what is the minimum amount of times ...
CrSb0001's user avatar
  • 1,622
1 vote
1 answer
120 views

A Hidato, but with no given numbers?

I can be a bit evil sometimes. Today, I am going to give you a Hidato with no numbers! It gets worse: This puzzle is on a Mobius Strip Y[1] However, I will give hints as to what the numbers are, so ...
CrSb0001's user avatar
  • 1,622
0 votes
2 answers
109 views

Minimum function optimization puzzle #2

Previous puzzle Take this puzzle of mine I created about an hour ago Take two functions, $f(x):=x^2$ and $g(x):=x-3$. Starting from $x=0$ and applying these functions as needed, what is the minimum ...
CrSb0001's user avatar
  • 1,622
1 vote
1 answer
173 views

Is my solution to a mathematics puzzle I created the most efficient solution there is to it?

Here's a puzzle of mine that I created around 2 hours ago: Let $f(x):=x^2$ and $g(x):=x-4$. Starting with x=0, what is the least amount of times you need to apply the functions $f$ and $g$ so that at ...
CrSb0001's user avatar
  • 1,622
9 votes
1 answer
721 views

A Hidato, but with a complex twist!

Today's Hidato puzzle has a pretty complex twist. What is the twist, you ask? This is what the twist is: There are three different colors: Yellow: Represents a prime number Green: Represents a ...
CrSb0001's user avatar
  • 1,622
8 votes
1 answer
372 views

Shuffled binary numbers version 2

Here are 0 to 15 in binary: 0 1 10 11 100 101 110 111 1000 1001 1010 1011 1100 1101 1110 1111 I have shuffled and concatenated them to obtain the following strings:...
Dmitry Kamenetsky's user avatar
7 votes
2 answers
748 views

Shuffled binary numbers

Here are 0 to 15 in binary: 0 1 10 11 100 101 110 111 1000 1001 1010 1011 1100 1101 1110 1111 I have shuffled and concatenated them to obtain this string: ...
Dmitry Kamenetsky's user avatar
4 votes
3 answers
1k views

an esoteric matchbox

Seeing a vast repository of matchstick puzzles, Professor Moriarty determined to create one of his own. Behold, his greatest crime yet, the best and worst matches puzzle to ever grace this earth with ...
MWQOJYNWQA's user avatar
9 votes
1 answer
385 views

Fitting snakes in a cage

11 snakes are in a 6x11 rectangular cage (grid) in a zoo. Each snake is a different length, from 1 to 11. No snakes may overlap. No spaces are empty. Each of the 6 rows may contain at most 2 snake ...
Amoz's user avatar
  • 26.3k
3 votes
2 answers
706 views

The Diamond of Columbus

There are up to flipping / rotation 12 distinct pentominoes. Can you fit them without overlap in the white area?
loopy walt's user avatar
  • 20.5k
10 votes
4 answers
2k views

A Prime Number equation using all nine digits once

Create an equation with the following conditions All numbers must be one or two digit prime numbers You can only use + and - and = No other math operators You must use all the nine (single) digits (...
RogerA's user avatar
  • 6,049
10 votes
2 answers
492 views

Shiny cryptarithm

Here's a little puzzle I made today: $$\sqrt{\text{ILLUMINATE}^{\mathstrut}} = \text{LIGHT}$$ Most usual rules of alphametic puzzles apply here: the same letter always represents the same digit, and ...
Greg Martin's user avatar
  • 1,160
19 votes
3 answers
2k views

Playing Mastermind against an angel and the devil

This puzzle is based on a card game. There are 7 suspects and 3 of them committed a crime. The game contains 35 cards that contain the 35 possible choices of 3 out of the 7 suspects. One card is drawn ...
quarague's user avatar
  • 1,841
12 votes
1 answer
810 views

27 spaces, 27 curious places

Grid 1: Grid 2: Grid 3: Find the meaning behind these images. Hint 1: Hint 2: Hint 3:
web adventurer's user avatar
3 votes
1 answer
243 views

Justifying a redouble

This puzzle is derived from a real game of bridge I played on Bridge Base Online. I was sitting North on board 9 (N dealer, E-W vulnerable) and the bidding turned out like this: West North East South ...
Parcly Taxel's user avatar
  • 7,251
0 votes
1 answer
157 views

Techno-Culinary Brain Teaser: Unravel the Code in the Kitchen

The answer is one word. The rebus:
web adventurer's user avatar
2 votes
0 answers
277 views

Find the ciphering method 4

Link to the entire series. The message: ...
web adventurer's user avatar
6 votes
1 answer
391 views

Find the ciphering method 2

Link to the entire series. The message: 3, 53, 48751, 9247757, 294914580539 The answer is a 13 letter word: UNDERSTANDING Hint 1:
web adventurer's user avatar
2 votes
1 answer
285 views

Find the ciphering method using deciphered message

Link to the entire series. Ciphered message: ...
web adventurer's user avatar
0 votes
0 answers
74 views

Find the largest number with unique digits, that is divisible by each of its digits [duplicate]

Find the largest number with unique digits, that is divisible by each of its digits. For example 132 has unique digits and is divisible by 1, 2 and 3. But it is not the largest such number. Can you ...
Teodor Dyakov's user avatar
32 votes
13 answers
8k views

2 vs. 1.005^200

Without using a calculator or a computer can you determine which of these two numbers is bigger: $2$ or $1.005^{200}$ ? I saw this puzzle in a YouTube video, which I will post later.
Dmitry Kamenetsky's user avatar
-2 votes
1 answer
117 views

Fill a 4x4 grid with minimal sum of positive integers in a way that adjacent cells contain numbers of different parity

Find a 4x4 grid containing 16 unique positive integers with minimum sum, such that adjacent numbers have different parity.
web adventurer's user avatar
6 votes
1 answer
311 views

The Nine Gardens Of Eden

This puzzle is part of the Monthly Topic Challenge #11: Now in 3D. There are nine distinct known three-cell Garden of Eden patterns in the Life Without Death cellular automata, including the two well-...
Scratch---Cat's user avatar
1 vote
1 answer
266 views

A take on custom ciphers

There is something hidden in the text below. Can you find out what it is? Note: no computers or tedious work required. ...
DL33's user avatar
  • 779
12 votes
3 answers
4k views

I Hate Traffic And So Do You

I need to travel through the city from my house to school, but the traffic is horrible right now. I can only move along the city's grid with the following conditions: • blocks with traffic (marked in ...
RonnieChen's user avatar
2 votes
1 answer
251 views

The minimalist game master [closed]

A game master tells his party of players that he has converted to the school of minimalism, and is going to do away with all of his dice in the campaigns they play from now on. In the place of dice, a ...
Feryll's user avatar
  • 2,349
0 votes
0 answers
154 views

Puzzle "railway game set"

Alisa completes a railway game set which allows us to make various closed railway routes with crossroads. It is need to put the “rails” parts in the kit, as well as four types of “crossroads”: corner (...
Nick's user avatar
  • 1,695

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