Chess: take the Knight's tour online

The Knight's tour is a traditional chess problem where a lone knight is placed on a chess board and must visit each square only once. You can play this perfectly simple free implementation created by u/psrwo on Reddit. The source code is at github. The knight is randomly placed at the outset.

I can't visit more than fifty-something squares, because I'm terrible at stuff like this. Read the rest

Highlights from the Red Bull Rubik’s Cube World Cup

The Red Bull Rubik’s Cube World Cup was held November 17 in Moscow. Competitors squared off in four events:

3x3 Speed Cubing - solving the Rubik’s Cube as fast as possible; Fastest Hand - a challenge that solves the Rubik’s Cube with only one hand; Re-Scramble - pits competitors trying to replicate a computer generated pattern from another cube as fast as possible and; 3x3 Female - a track exclusively for female competitors.

Here are highlights from the event, which was attended by Erno Rubik himself:

Red Bull has also posted a series of instructional videos on solving Rubik's Cubes:

Read the rest

Where is the 5th pig?

This is an anti-fascist puzzle made in occupied Netherlands circa 1940. Can you find the 5th pig? (Hint: Al Jaffee would have no problem finding it.)


[via r/interestingasfuck] Read the rest

An escape room where you have to remove your booby-trapped pants before they explode

Pants//Off is a mobile escape room based on the concept that you're a secret agent who tried on cutting edge pants only to discover they've been sabotaged and rigged to explode. Can you get them off within 10 minutes?

After getting locked into the pants, the player has to solve all sorts of puzzles using the odd array of tools stuffed in their pockets.

Here's a glimpse of the action:

(Via Max Temkin.) Read the rest

Review / Manifold Garden

William Chyr’s abyss stares back. It's a good puzzle game, too.

Can you solve the secret sauce riddle?

Alex Gendler of TED-Ed challenges you to figure out where the recipe for a top-secret sauce recipe is located.

Below: All the information in one screenshot.

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Regular expression crossword puzzles!

I'm on record as being a big supporter of learning regular expressions (AKA "regexp") -- handy ways to search through text with very complex criteria. It's notoriously opaque to beginners, but it's such a massively effective automation tool and drudgery reliever! Regex Crosswords help you hone your regexp skills with fiendishly clever regular expressions that ascend a smooth complexity gradient from beginner to expert. (via Kottke) Read the rest

The problem with 'The Monty Hall Problem' was Monty Hall

The Monty Hall Problem is a probability puzzle, but the actual problem with the Monty Hall problem was just Monty Hall. Probability doesn't really matter if the game show host has free will and a willingness to mess with you.

This is the classic 'three doors' problem, where there is a prize behind one door and nothing behind the other two. After you, the contestant, picks Door 1, the Host then opens Door 2 and shows you it is empty. The host then offers you a chance to switch your choice to Door 3? Do you take it?

If probability were the only thing at play, yes. However, as Monty Hall noted: if the host is not bound by any rules, they can mess with you and are not predictable.

Monty was the problem, hence the name of the problem.

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Svalbard: a "puzzle story" created by Lavie Tidhar and Jake Olefsky

Jake Olefsky writes, "I am a puzzle author interested in story telling. I recently worked with award winning author Lavie Tidhar to create an interactive sci-fi puzzle story called 'Svalbard' that we just published on a new website that will hopefully have more puzzle stories in the future. The idea is that you read a chapter and then solve a puzzle to unlock the next chapter. The story branches in a non-linear fashion, so you can take different paths to the conclusion. In Svalbard you travel along with Mai as she explores a utopian post-apocalyptic world and discovers ancient time vaults, forgotten robot enclaves and slumbering super computers. There are over 30 puzzle to solve and secrets to discover in this 20 chapter short-story." Read the rest

Watch a robot solve a Rubik's cube in less than half a second

We previously posted about a robot that solved a Rubik's Cube in .637 seconds. Read the rest

Can you solve the two-fuse puzzle?

Here's a good riddle from Brian Brushwood of Scam Nation.  He found it in Book of Riddles by Fabrice Mazza and Sylvain Lhullier

Imagine that you're making a magic potion. You're a wizard with a long beard. But -- the potion only works if you wait exactly 45 minutes before you stir it. If you stir it before or after the potion's totally ruined. You don't have a smartphone. You don't have a watch. You don't have any kind of time measuring device. What you have is two fuses of irregular consistency. The one thing you know for a fact is that it takes an hour for each of these fuses to burn from one end to the other. How do you use these to measure exactly 45 minutes?

Image: Scam Nation/YouTube

I'm still trying to figure this one out, so I'm not looking at the comments yet! Read the rest

Two 'Rubik’s Race' players compete at mind-boggling speed

Rubik's cube for two as a race. That's Rubik's Race. Read the rest

Wooden fractal curve puzzles

Martin Raynsford makes beautiful and intricate wooden puzzles with space-filling fractal curves and is kickstartering a set of four.

The pattern is a single line that crosses all of the two dimensional space without ever repeating. The puzzles follow these simple rules to break the line into multiple pieces that are almost identical but are actually unique. The pieces are so similar in style that once they are placed into the puzzle it is hard to see where the pieces are. The puzzles can be tricky to solve even if you have the solution on hand.

The puzzles are made from a high quality 3mm, 6 Ply, BR Grade, Birch Laser Plywood sheet. It shows the natural look of the wood and will have natural colour variations. Each puzzle is 200x200mm in size, the pieces are 3mm thick and the whole puzzle inside the tray is 6mm thick.

For immediate gratification, you can also hit up his Etsy Store; the Cryptex box (Note that it's for PLANS only, you'll need to cut and make it yourself) looks like a great gift for the smartest egg in your family. Read the rest

Two lateral thinking puzzles

Here are three two lateral thinking puzzles that were new to me. They're from the book, Lateral Thinking Puzzles (1991), by Paul Sloane.

Death in the Field

A man is lying dead in the field. Next to him is an unopened package. There is no other creature in the field. How did he die?

Death in Rome

Mr. Jones is reading his daily newspaper. He read an article with the following headline: “Woman dies in holiday accident.“ It goes on to say, “Mrs. Rigby-Brown, while on holiday with her husband in Rome, fell to her death from the balcony of her seventh-floor room.“

Mr. Jones turns to his wife and says “That was not an accident. It was murder.“ He had never met either of the Rigby-Browns, so how could he know it was murder?

Image by S.Borisov/Shutterstock Read the rest

The broken bracelet puzzle

One of my favorite puzzle books as a kid was Perplexing Puzzles and Tantalizing Teasers, by Martin Gardner. It had fun "real life" type problems (how can you drive an 11-foot-9 truck under a bridge with 11-foot-8 clearance?) and it introduced me to palindromes ("Straw? No, too stupid a fad. I put soot on warts.")

Here's another "real life" puzzle: a person brings four pieces of a broken bracelet to a jeweler and asks him to repair it. The jeweler says he charges $1 for each link he cuts apart and welds together again. "Since I have to cut and weld four links, the job will cost you four dollars." But the customer correctly tells the jeweler he can make the bracelet by cutting and welding only three links. How? Read the rest

How to get better at solving puzzles

I've been reading a 1978 book called The Art of Problem Solving, by Russell L. Ackoff. (Used copies sell for $7 including shipping on Amazon). At the beginning of the book, Ackoff tells about the time his school-age daughter came home with a familiar puzzle. On a piece of paper, there are nine dots arranged in three rows of three, like this:

The challenge is to put a pen on the paper and, without lifting the pen, draw four straight lines that go through all nine dots. You probably remember this puzzle, because it's been around for a long time. Ackoff remembered it, too, but he'd forgotten the solution. But he came up with another way to solve it. He folded the paper so two rows of dots touched each other and used a felt pen to draw through both rows with one stroke. Then he unfolded the paper and drew two more lines to cover the rest of the dots.

When Ackoff's daughter went to school the next day, she started to show the teacher the solution her father came up with. As soon as she began folding the paper, the teacher stopped her and said she was not allowed to fold the paper, even though the instructions didn't say she couldn't.

"This is how creativity is suppressed, although usually not so overtly," writes Ackoff. "The teacher made it clear to her class that the objective of the assignment was not to find a solution to the problem, but to find the solution she knew and could pretend to have discovered on her own. Read the rest

Meet one of the creators of the New York Times crossword puzzle

Magician David Kwong moonlights (er, daylights?) as a crossword puzzle creator for the New York Times. In the parlance of the craft, he is a "cruciverbalist," one who is adept at making, or solving, crossword puzzles. (Wired) Read the rest

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