In this Scientific American video, Rubik's Cube master Ian Scheffler, author of the new book Cracking the Cube, explains some of the math behind "speedcubing." Scheduler's book sounds fascinating even though the only way I could get my Rubik's Cube solved is to hand it to my 10-year-old son's friend Luc who was the first to dazzle me with the fine art of speedcubery.
From the description of Cracking the Cube:
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When Hungarian professor Ernő Rubik invented the Rubik’s Cube (or, rather, his Cube) in the 1970s out of wooden blocks, rubber bands, and paper clips, he didn’t even know if it could be solved, let alone that it would become the world’s most popular puzzle. Since its creation, the Cube has become many things to many people: one of the bestselling children’s toys of all time, a symbol of intellectual prowess, a frustrating puzzle with 43.2 quintillion possible permutations, and now a worldwide sporting phenomenon that is introducing the classic brainteaser to a new generation.
In Cracking the Cube, Ian Scheffler reveals that cubing isn’t just fun and games. Along with participating in speedcubing competitions—from the World Championship to local tournaments—and interviewing key figures from the Cube’s history, he journeys to Budapest to seek a meeting with the legendary and notoriously reclusive Rubik, who is still tinkering away with puzzles in his seventies.
Getting sucked into the competitive circuit himself, Scheffler becomes engrossed in solving Rubik’s Cube in under twenty seconds, the quasi-mystical barrier known as “sub-20,” which is to cubing what four minutes is to the mile: the difference between the best and everyone else.
If you’re fascinated by paper art and pop-up books, then the name of 51-year old Robert Sabuda will resonate like that of a Zen master. He’s a legend in the world of children’s books, paper design, and engineering, with many famous books to his credit (my favorites are The Wizard of Oz and Alice in Wonderland).
Kind of like a pop-up book equivalent of The Avengers, Sabuda has embarked on a new adventure in collaboration with Shelby Arnold and Simon Arizpe called The Armchair Detective Company. You can also follow them on Facebook. Read the rest
I bought Thinking Physics, by Lewis C. Epstein in 1984. It's one of my favorite books of brain teasers. They are designed to help you gain a qualitative, intuitive sense of physics. The author stresses that after you read each of the many charmingly illustrated problems in the book, you should put the book away and take your time running a simulation of the problem in your head. This is great advice. Read the rest
Here's a puzzle from Martin Gardner's "Mathematical Games" column, which ran for many years in Scientific American. I found it in his anthology, My Best Mathematical and Logic Puzzles, which is only $3.42 on Amazon.
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There is a simple procedure by which two people can divide a cake so that each is satisfied he has at least half: One cuts and the other chooses. Devise a general procedure so that n persons can cut a cake into n portions in such a way that everyone is satisfied he has at least 1/n of the cake.
Here's a puzzle from Martin Gardner's Mathematical Games column, which ran for many years in Scientific American. I found it in his anthology, My Best Mathematical and Logic Puzzles, which is only $3.76 on Amazon.
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Imagine that you have three boxes, one containing two black marbles, one containing two white marbles, and the third, one black marble and one white marble. The boxes were labeled for their contents – BB, BW, WW – but someone switched the labels so that every box is now incorrectly labeled. You are allowed to take one marble at a time out of any box, without looking inside, and by this process of sampling you are to determine the contents of all three boxes. What is the smallest number of drawings needed to do this?
The Colossal Book of Short Puzzles and Problems is a 512-page collection of puzzles from the Martin Gardner's beloved Scientific American column. The easier puzzles are at the front of each section, and become more difficult as you progress. Here's one of the easy ones:
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In the United States at least eight coins are required to make the sum of 99 cents: a half-dollar, a quarter, two dimes, and four pennies. Imagine yourself the leader of a small, newly independent nation. You have the task of setting up a system of coinage based on the cent as the smallest unit. Your objective is to issue the smallest number of different coins that will enable any value from 1 to 100 cents (inclusive) to be made with no more than two coins.
For example, the objective is easily met with 18 coins of the following values:
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90.
Can you do better? Every value must be obtainable either by one coin or as a sum of two coins. The two coins need not, of course, have different values.
The new book, Einstein's Puzzle Universe, by Tim Dedopulos, is a compendium of good physics and logic problems. Here's one for you to solve:
Imagine that there is an even rope of negligible weight draped over a wheel, which permits it to slide perfectly freely. Equal lengths of the rope descend from either side. On the left side, the rope ends in a 10 kg weight. On the other side, perfectly level with the weight, is a young chimp, also weighing 10 kg.
When you give a signal, the chimp will start climbing the rope. Which of the two, the chimp or the weight, will reach the top first?
Martin Gardner wrote Aha! Gotcha: Paradoxes to Puzzle and Delight and Aha! Insight in the early 1980s and I love them both. Both books have excellent brain teasers with charming illustrations. They are both out of print, which is criminal, but Amazon has used copies for $0.01 (plus $3.99 s&h).
Your rich, eccentric uncle just passed away, and you and your 99 nasty relatives have been invited to the reading of his will. He wanted to leave all of his money to you, but he knew that if he did, your relatives would pester you forever. Can you solve the riddle he left for you and get the inheritance?
Here's the full lesson, taught by Lisa Winer for TED Ed.
Rush Hour Shift is an entertaining twist on the classic get-the-car-unstuck logic game. Instead of a single player working through pre-designed puzzles, now there are two players working against each other in a constantly changing landscape. The manual includes instructions for ten basic board set-ups to start. Following these instructions, players are positioned at opposite ends of the board while cars of different sizes and colors are placed between them. The object of the game is to get your car (Silver versus Gold) to the other side of the board.
Each player is dealt four cards, and on your turn you play one of your cards and do what it says. There are four card types: Move, Shift, Slide, and Move & Shift. Move cards allow you to move any car (except your opponent’s car) the number of squares indicated on the card. You can also strategically split up the number among cars, so if you play a three you could move one car two spaces and another car one space, or you could move three cars one space. Shift cards allow you to move the board itself, and this is probably the coolest aspect of the game. The game board is built with three interlocking pieces, and when you play a shift card you can move either of the end pieces as far as you want. So you can literally remove the path from your opponent so they have nowhere to go. Slide cards allow you to move as many spaces you want until something blocks your path. Read the rest
Everyone has their favorite space ship. For some, it’s the Enterprise, for others it’s Red Dwarf, or Battlestar Galactica. It might even be the TARDIS. But for my money, it is, and has always been, The Millennium Falcon. The ship that made the Kessel Run in less than twelve parsecs. The fastest hunk of junk in the galaxy. The iconic space ship that helped launched one of the biggest movie franchises of all time.
Now, in this puzzle from Tenyo, our favorite freighter has been given a pop-art makeover, complete with sporty red background and stylized lettering. She’s posed at a jaunty angle, ready to jump into light speed the second Chewie gets it working again. Really, it’s a fun cross between an '80s car poster and the movie poster for The Endless Summer.
The puzzle itself measures about one foot by one foot when assembled. It is 144 pieces, but with only three colors, it is not quite as easy as the piece count might suggest. It is made from standard puzzle quality cardboard; the pieces fit together very well, with little coaxing or massaging needed to assemble the puzzle. The image is bright, clear and solidly printed on the cardboard.
The puzzle set includes a panel - frame, plastic cover, white card stock puzzle back, and cardboard frame back - as well as puzzle glue, cardboard glue scraper, and a string to hang the frame. The puzzle sits in the frame well and the plastic cover sheet allows framing without gluing for those who may wish to do the puzzle multiple times. Read the rest
I found these matchbox size wood puzzles at a general store in Colorado and bought three of them. There are a bunch of different ones in the series and I plan to get them all because they are almost like magic tricks and it’s fun to challenge your friends by showing them the end result (without letting them see the process of solving them).
The Baffle Board is a miniature version of an old classic known as the Red Goose puzzle. The challenge is to move the three beads from the loop of string on one side of the block to the loop on the other side. The printed solution included with the puzzle isn’t very clear, so here is a YouTube video, if you can’t figure it out.
Push N Pull is similar to the Red Goose, but a little easier to solve. The solution included in the puzzle is clear.
Brass Monkey is the hardest puzzle of all, but also the most fun. The challenge is to make a pyramid out of the six wooden pieces. The pieces tend to roll away as you work with them, so it helps to do this puzzle on a non-slippery surface, like a rubber computer mouse pad, or to support it with something like a stack of Post-It Notes. The included solution is not very clear, so here’s a YouTube video with the solution. – Mark Frauenfelder
Pocket-size wood puzzles
Matchbox Puzzlers By House of Marbles Baffle Board $3 Buy one on Amazon
Push 'N' Pull $3 Buy one on Amazon
Brass Monkey $3 Buy one on Amazon