Material added 27 November 2011
- Dr. Matrix and Friends
- A blog devoted to Martin Gardner is at drmatrix.org. I learned a particularly nice magic trick there. Make a sandwich from three coins, with the middle one small (such as quarter, penny, quarter). Drop the bottom two coins onto your other hand. The penny will flip to be under the quarter as it lands.
- Largest 3D Painting
- Joe Hill has put together a gigantic 3D painting, over at largest 3D painting.
- Barrel Roll Jump with Car.
- The Golden Gun bond film had the hardest car stunt ever done, and which also had one of the most unfortunate sound effects. Top Gear tried to recreate the car jump with twist, and went through an impressive amount of math to try to get it right.
- Erich's Holiday Puzzles
- Go in with 2011, and go out with 2012. You may pass through an operation several times, but not twice in a row. This and other puzzles are at Erich's Holiday Puzzles 2011.
- Complicated Music
- I was fooled by the YouTube posting John Stump - Death Waltz. It is true that Stump made some incredible looking sheet music, but it wasn't really meant to be played. But the piece actually sounds pretty good. It actually turns out to be a variation on music from the computer game Touhou project, named Flandre's theme, or U.N. Owen was her?. It has a great illustration of music approaching a limit point. I also learned about Circus Galop. Even harder seems to be the piece Night of Nights. And learned about the great free midi program, Synthesia.
- Rolling dice Sudoku
- Nevzat Moraç: RULES
1) Initial positions of the dice: Place them in any two squares and in any position you wish.
2) The dice are to be rolled 90 degrees to any adjacent square.
3) Give the top number of the die to the square you step upon.
4) You annihilate the number you step upon if there is any.
Get the position
2 3 6 5 1 4
1 5 4 6 3 2
5 4 1 2 6 3
3 6 2 4 5 1
6 2 3 1 4 5
4 1 5 3 2 6
Solution here. As a warmup, with one die in a 2x6 rectangle, get numbers 1 to 6 in the top row. [Ed - Is doing this with one die provably imposible?]
- Worst Poker Hands
- At Wolfram, there is a 15% off sale on Mathematica Home Edition until December 31. Over at Wolfram|Alpha, which might be making some announcements soon, you can look up things like the worst poker hand, which might help if you ever try out one of the internet poker sites. There are several different variations of poker games you can play, each of them has slightly different statistics for win chances.
Material added 11 11 11
- George Sicherman: A polyomino tetrad is four congruent polyominoes joined so that each is adjacent to the other three. Karl Scherer, at his website Atlantis, shows two 9-omino tetrads. Can you make a tetrad from an 8-omino? [Solutions attached.]
- Penrose Tiles and Trapdoor Ciphers shows Scott Kim's holeless symmetrical tetrad made from a symmetrical 26-iamond. Gardner asks whether such a solution exists using a polyiamond with fewer edges (not cells). 1. Find a 12-iamond with mirror symmetry that forms a symmetrical tetrad. [Unique solution.] 2. Find a 22-iamond with mirror symmetry that forms a holeless symmetrical tetrad. [I'm not sure it's unique.]
- Scherer's Tetrad page shows a tetrad made from a 14-omino with mirror symmetry. 1. Make a tetrad from a 13-omino with mirror symmetry. 2. Make a tetrad from a 13-omino with birotary (point) symmetry. [Unique solutions.]
- In Penrose Tiles and Trapdoor Ciphers, Martin Gardner shows a holeless 12-omino tetrad by Scott Kim. [Attached.] Puzzle: find a holeless 11-omino tetrad. [Unique solution attached.] I am not sure it is fair to present this as a puzzle. However, I am curious to know whether anyone else can solve it, by hand or otherwise! Dr. Scherer's site has a 14-omino solution. [EDIT -- Egor Skriptunoff: A man on russian forum had it solved in 4.5 hours with pencil and 5 sheets of paper. Original Russian, English Translation] [And a reply quote from George Sicherman -- "Knowing something is possible makes it more solvable."]James Noir's Hollywood CrimesA Nintendo 3DS game has rather good puzzles by Oscar van Deventer, Andrea Gilbert (clickmazes, River Crossing), James Stephens (puzzlebeast, Anti-Virus), Tom Jolly, and the Grabarchuk family (Big, Big Book of Brainteasers). Not really worth getting unless you've already got access to a 3DS, but it's good to see some top puzzle talent working together.
- Oskar's Four Bit Maze
- A good write-up on Engadget talks about Oskar's Four Bit Maze. Oskar is also now the holder of a Guinness World Record for the Largest Order Rubik's Cube.
- 11/11/11 11:11:11
- Wolfram Research has a blog on 11/11/11. It's _ _el_-ev__en___, _el_-_eve__n_, _elev_e__n_ _el___e _ven_ ___ _e_le___ven___. (A well-evidenced, self-reverent, televiewing welcome event for reflectiveness.)
Material added 22 September 2011
- New Grabarchuk Book
- The Big, Big, Big Book of Brainteasers is the best new puzzle book I've seen in years. Often, when I get a puzzle book, I'm hoping to get at least a handful of puzzle types I haven't seen before. This book has hundreds of puzzles completely new to me. Every page is loaded with fantastic, colorful puzzles, and full answers for each puzzle are in the back.
Some sample puzzles (but without the lovely graphics):
#162: On a standard QWERTY keyboard, find 3 consecutive letters that make an acute triangle.
#181: An 8 slice pizza was eaten by 4 people. No-one ate more than the other 3 combined, and everyone had a different number of slices. How many did each person eat?
#384: A 24-hour clock shows the time 01:23, where the digits are in an increasing arithmetic progression. In this case, they increasing with constant of 1. How many times in 24 hours will this property be seen?
- US Sudoku Qualifier Puzzles
- The US Sudoku qualifying puzzles will take place online Saturday, September 24. The puzzles will be downloadable by anyone who has registered on Friday, and the decryption key will be available at the start of the event. This year's puzzles were designed by Thomas Snyder and Wei-Hwa Huang, authors of "Sudoku Masterpieces" and designers of the 2010 World Sudoku Championship puzzles
- Google+, Facebook, and Twitter
- Most of my online time recently has been at either Demonstrations or Amazon. But I am also trying to do things with Facebook, Twitter, and Google+. There is also the MathPuzzle mailing list at Yahoo Groups.
- Martin Gardner Events
- There will be another series of worldwide events in October, in honor of Martin Gardner. You can take a look at the event map at g4g-com.org. I'll be at the Champaign IL event.
- Square Enneiomino Compatibility
- George Sicherman: The square enneiomino is a polyomino made of nine squares joined to form a 3×3 square.
The compatibility problem is to find a figure that can be tiled with each of a set of polyforms. Here I show minimal known compatibility figures for the square enneiomino with other polyominoes. If you find a smaller solution or solve an unsolved case, please let me know. (He also wrote up Voided Square Octomino Compatibility).
- 5V = 5W = 5Y
- George Sicherman: Years ago Livio Zucca solved pentomino triple 5V=5W=5Y. His "Remembrance" website shows the solution. It has 90 tiles! I have always regarded it as a fat target. Yesterday I found a solution with 72 tiles. That's still pretty fat! Can anyone improve on it?
Material added 31 Aug 2011
- At squaring.com, Stuart Anderson has finished compiling the Order 29 Perfect Squares. I've made some findings from the Imperfect squares, for example that the Mrs. Perkins Quilt of size 1099 has order 27. Note the two squares of size 324 -- this square cannot be found directly from 3-connected graphs.
- Puzzle Design Competition
- The 2011 Puzzle Design Competition has announced the winners.
- Spiral Burr and Burr Tools
- Oskar van Deventer's latest puzzle is the Spiral Burr. This is one burr puzzle that the recently updated Burr Tools (now available for Mac) won't be able to help you with.
- Morpion Solitaire has New Record
- Chris Rosen has upped the record for Morpion Solitaire up to 178 moves.
- Krazy Dad Phylotaxis Music
- Krazy Dad has a lot of excellent puzzles and animations. I particularly liked the below sound animation of a phylotaxis spiral.
- Wolfram Alpha CDF Player
- The Computable Document Format (CDF) has been turned on over at Wolfram|Alpha for appropriate area.
- Extreme Magnets
- The artist Magnenaut used 8754 spherical magnets to make the below picture.
Material added 21 Jul 2011
- CDF - Computable Document Format
- My longtime employer Wolfram Research (makers of Mathematica) has launched the Computable Document Format. Something like this has been available for awhile at the Demonstrations Project, where I have a few hundred math demos. CDF comes with a set of browser plugins, allowing interactive online programs with relative ease.
- Karl Wilk -- I'd like to offer this assembly of polyominoes that I call 'Polyominium'. It contains the 6473 polyominoes of order 1 thru 10, with no extra holes beyond the ones contained in the single pieces. The decomino portion was done in the past year, the enneominoes and inward was done in 2008 and can be seen on Kate Jones Kadon website (labelled 'Cyclops' in tribute to Arthur C. Clarke). You'll notice that the radius is approximately doubling with each higher order of polyominoes. This I believe is related to the finding of Jensen and Guttmann: their value of tau = 4.062570(8), is basically a ratio of areas, if I'm not mistaken. Although I've used the pieces with holes and they haven't, the difference here is small. [Ed - Click on the 'small' version below to see the big version. For more Polyomino goodness, try the Poly Pages by Andrew Clarke. Karl also built a large polyhex construction.]
- Seven Euphoric Pentahexes
- If a polyform can make the same shape as all other polyforms of the same size and order, it is called Euphoric. Thanks to two fortuitous discoveries, George Sicherman has increased "Five Euphoric Pentahexes" to "Seven Euphoric Pentahexes". The below is a small piece of the larger page.
- Disks in Rectangles
- If N disks are in a rectangle with perimeter 4, what is their greatest possible radii sum? David Cantrell tackled the problem for Disks in Rectangles. Most of these were solved with Mathematica (mentioned above).
Material added 26 Jun 2011
- "It's Nonconvergent!"
- Futurama is back, with the below clip Infinite Benders having some fun math.
- Mark Setteducati in WSJ
- The Wall Street Journal has a great article about magician and inventor Mark Setteducati.
- Various Amazon Reviews
- I've been trying out a lot of reviews lately, for things like Mathematica Home Edition (Windows, Mac, Linux), Kindle programs (Notepad, Sticky Notes, Futoshiki, Strimko, Calendar, Pirate Stash), Kindle books (100 Puzzle Quizzes, Little Miss Mary, LA Noire Storybook, Panamindorah), Print books (Not a Wake, Playful Brain, Adventures of Tintin), Various computer games (Zelda 3D, Ghost Recon 3D, Infamous 2, LA Noire), Various puzzles (Athena, Rattle, Thinkfun Tilt). I wrote enough reviews to get into the Amazon Vine program, where I've taken a look at things as varied as dog treats and sphygmomanometers. I freely admit I have no idea what I'm doing, but I do seem to like stamping my opinion on things. I have about a thousand puzzle books I want to review, but that's tricky. Many of them don't have new material. Others are excellent books, but I found them difficult.
For example, I haven't figured out how to review Games of No Chance 3. It's an excellent book, but much of it will be mysterious to those that haven't read Winning Ways or Games of No Chance. I found it hard, and I didn't have any instant take-aways from it. I have hundreds of books like this that don't fall into the "easy to recommend" pile.
- 10,000 Year Clock
- Speaking of Amazon, Jeff Bezos will be funding a 10,000 year clock, as recently described in a Wired article. Another website is the Longnow Foundation. Part of the clock is an Equation of Time cam that was modeled by Stewart Dickson (available as a demonstration).
- NINETY/TEN + TWELVE - THREE = TWENTY + ELEVEN - THIRTEEN.
- Mike Keith, who runs cadaeic.net (c=3, a=1, d=4, a=1, e=5, i=9, ...), found the above spectacular anagram. The only anagram of note I found last month was "Saint Leo IV ~ is not alive", not nearly as interesting. Mike has greatly expanded his page on alphametics, as a result of his computer searches. He's also written an incredible Alphametish Poem.
- From a Hula Hoop's Viewpoint
- The youtube video Hula Hoop Cam shows the point of view of a hula hoop.
- Hexapent Oddities
- Dear Ed, I've posted the Hexapent Oddities. Also, I've been told that #178 of my crossword-sudoku puzzles was unfairly and unreasonably hard, so I've re-clued it for mortals.
- Small Simple Graphs
- I liked the Small Simple Graphs sandbox at gfredericks.com.
- Autodesk 123D
- Autodesk has launched a free 3D modeling program.
Material added 5 June 2011
- Mini-Go Results Greatly Improved
- For years, the expert on mini-Go has been Ted Drange, who used to cheerfully trounce me in postal play. Recently, Erik van der Werf and Mark H.M. Winands, with help from the program MIGOS, and even more help from Ted Drange, have greatly improved mini-Go results. Further detail is given in their paper, Solving Go for Rectangular Boards. For example, the optimal game for the 3x7 board is below.
- Games and Puzzles Journal
- G P Jelliss has put the whole set of the Games and Puzzles Journal 1-18 and Games and Puzzles Journal 19-44 at his site mayhematics.com.
- The Game of Ergo
- In the game of Ergo, you must prove your existence, while disproving your opponent's existence.
- Favorite Number
- Alex Bellos has set up the site Favorite Number, in case you might have one.
- Optical Illusions of the Year
- The 2011 Illusion of the Year contest has wrapped up, with some very intriguing new illusions.
- Fund a Wooden Cube Puzzle
- The site kickstarter.com lets you propose and give incentives for a project. Michael Reilly is trying that with an 8 piece wooden puzzle he calls Reilly's Cube.
- Texas Holdem Poker Stacked Decks
- Ben Joffe has greatly extended an earlier analysis of Ice Cold Texas Holdem Decks. Basically, indicate a number of players, and a position on the table, and his computer program has a deck so that the person will always win, no matter how the deck is cut. There are some fascinating patterns that pop out.
- Morpion Record
- A new record in Morpion Solitaire by Chris Rosin -- 177 moves.
- Magic Square Record
- New smallest known magic square of 4th powers: a 16x16 by François Labelle. The previous record was a 36x36. In the news section at multimagie.com.
- I would love to get some HoMgZn crystals.
- Incredible Paper Sculptures
- Johan Claes: You probably want to dedicate some space to these wonderful objects (michael-hansmeyer.com), all created from paper (lots of paper). Very interesting how computational objects don't stay limited to images and start invading the real world. It's quite unclear how these sculptures are really created. Another intriguing topic is whether they could be made strong using other materials.
- Snakes on a Plane
- The Al Zimmermann contest "Snakes on a Plane" that took place in fall 2006 has gotten a number of improved solutions recently.
- Newt Gingrich said a few Sunday's ago that "Any web posting quoting what I said on Sunday is a lie."
- Interesting Elliptic Curves
- I had a program sample a few billion elliptic curves, and pulled out a thousand Elliptic Curves on a Small Lattice that went through a lot of lattice points. For example, the curve below has 17 points on the lattice, with 32 lines going through 3 points.
- Some impressive engineering went into this Trackmania racetrack.
- With Keith Devlin and Colin Wright
- I gave a talk at the Recreational Mathematics Colloquium II in Evora Portugal at the end of April. Here I am with Keith Devlin and Colin Wright.
- One of the items shown there was a Pinwheel Tiling quilt by Andreia Hall.
- On the plane flight, I found the following magic hexagon. If a number is repeated on a line, only use it once. Notice that 1 and 2 do not share a line. There is an inverse of this hexagon, where anything not sharing a line here IS sharing a line.
- Neil Bickford in NYT Blog
- Neil Bickford ran a guest blog on Numberplay, namely a Triplet of Time Puzzles.
- Blocked, on the Kindle
- Rush Hour is a great puzzle game, designed by Nob Yoshigahara. A poor copy called Blocked isn't earning me any reviewer points for pointing out the origin. Am I in the wrong for pointing out in my review that this is unethical?
Material added 25 April 2011
- Blokus Discoveries
- Toby Gottfried: The game of Blokus is based on placing polyominoes on a board with only corner-to-corner touching. For sizes 1-5, there are in total 21 polyominoes, comprising 89 squares. I have found ways to place all of them in rectangles with corner-to-corner touching only for the following sizes, with other sizes being either trivial or impossible
150 = 5 x 30
(152 = 8 x 19 - all pieces except the monomino)
153 = 9 x 17
154 = 11 x 14
156 = 12 x 13
These results and others related to Blokus I have on my Blokus Discoveries page. (Ed - Toby Gottfried's full site is also excellent)
- Octiamond tetriamond construction
- George Sicherman: I found these tetriamond-octiamond compatibilities and posted them to my Mixed Polyiamond page. Also, here's a puzzle for you. It's the last poem on my poetry page, written for a namesake and possible 23rd cousin of mine.
- Extreme Dot-to-Dot
- Gavin, who runs the site Doctor Dot, has sent me a PDF with a sample extreme dot problem.
Material added April 20, 2011
- Phonetic pangram
- Years ago, I came up with a phonetic pangram -- "Sheathing his sword, the big private helped an adult commonweath refugee." I was surprised to see it in the List of Pangrams at Wikipedia.
- Math Factor
- I visited the University of Arkansas last week, and happened to be visiting Chaim Goodman-Strauss at the same time as James Stephens of puzzlebeast.com, so we had an extended podcast for Math Factor. I also gave a talk on how computers are making it easy to be the first to take a serious look at many math problems, due to Moore's Law giving people of today a billion times as much computer power as people from a few decades back.
- How Round is Your Circle?
- The video How round is your circle? gives an excellent overview of many unusual round objects.
- Minsky Circle Problem
- Neil Bickford, Corey Ziegler Hunts, and Julian Ziegler Hunts are a trio of teenagers who have used their billion times as much computer power to take a serious look at the Minsky Circle Problem, with some fascinating discoveries.
- Pentagon 3-4-5
- George Sicherman tackled the 32 + 42 = 52 dissection problem at Math Magic for the pentagon.
- What is the fewest number of 45-60-75 angled triangle that can perfectly tile a square? Here is a solution with a flaw. I will offer a reward for a new solution equal to 100-(number of triangles) in dollars for a proper solution. There is a known solution with over 300 triangles. I've also put this problem at zombal.com.
- Geometry Expressions Newsletters
- I like the program Geometry Expressions a lot, and just started looking at their version 3.0 Beta. They have also put their Geometry Expressions Newsletter online.
Material added March 19, 2011
- Quantum Maze
- Over at ClickMazes, the Quantum Maze by Jonathan Welton is quite nice. An 8x8 grid starts empty, and every move of your piece creates some walls based on your direction and location. With that, you must visit all four corners. I also liked Andrea's Treasure Island puzzle.
- The Fuse Problem
- With the assistance of a lot of cannon fuses, I've made my first Youtube video, about the Fuse Problem. The original paper by Jeff Ericksen is Fusible Numbers. It took four takes to get even remotely close -- fuses are a terrible method for measuring precise amounts of time.
- Puzzle Event Calendar
- The site puzzlehuntcalendar.com is exactly what you might expect it to be.
- I like the sudoku variant Mejji.
- Spiked Math
- A good math-based webcomic is Spiked Math.
- Palago and Ordo
- The game Palago by Cameron Browne has been released, and now has a Palago entry in Wikipedia. A different recent game I liked is Ordo by Dieter Stein, where your pieces must stay connected.
- Squaring Updates
- Many updates have been added to Squaring.net, including new results in simple perfect squared squares.
- Always Composite
- Stan Wagon: The following numbers are always composite, and are likely the smallest such numbers.
381111111.....1 (proven smallest by L. Jones, p. 159, Table 4, Amer Math Monthly, Feb 2011)
407033333.....3 (likely the smallest - other possibles 410, 817, 1037, 1166, 2959, 3674)
891777777.....7 (proven smallest by Stan Wagon)
101759999.....9 (likely the smallest - other possibles 1342, 1802, 1934, 3355, 4420, 4499, 6664, 7018, 8578)
- Crosswords in Reader's Digest
- The Canadian Reader's Digest has started a free crossword puzzles feature.
- Hamiltonian Snakes
- Alexandre Owen Muniz: A couple of nice solutions to problems on my blog were contributed recently. George Sicherman found Hamiltonian circuits of the vertices in a 6×8 rectangular grid using the linear 3- and 4-sticks. Bryce Herdt found a semimagic magic 45-omino.
Material added 2 February 2011
- 17 Level Rubik's Cube
- Oskar van Deventer, the greatest inventor of mechanical puzzles the world has ever known, with Shapeways, has built the first 17-level Rubik's Cube. Also seen in Oskar's Shapeways Store. Now recently in Make magazine.
- Eternity II Ends in Current Form
- Monckton of Brenchley: "To all Eternity II addicts - Many thanks for your participation, and I am delighted that you enjoyed the Eternity II challenge. The final scrutiny date has passed without a winner, so the competition is now closed. Extension of time is not allowed under the rules. However, an electronic version of the puzzle is now being considered, so the solution will not be released. Look out for more interesting games and puzzles to follow!" [Ed - If you solve this puzzle, hold it until further details emerge. You can also look at my coverage of the first Eternity puzzle.]
- Knuth Books
- Two books by Don Knuth have been released. TAOCP4A: Combinatorial Algorithms and Selected Papers on Fun & Games. Here I am with both, right after the big snowstorm.
- Bob Harris Sudoku Puzzles
- One of the people mentioned in Knuth's Fun&Games, on page 656, is Bob Harris. Knuth discusses a 2009 Christmas sudoku. Bob has released 14 new puzzles of this type, the 2010 Christmas Squiggly Sudoku.
- Non-covering Polyominoes
- From Naoki Inaba: What is the smallest polyomino Q such that multiple copies cannot cover a given polyomino P without overlapping? His smallest solutions for the I and X pentominoes are below. At inabapuzzle.com (English trans), he's shown solutions for I and X, and several hexominoes. He's proven F, L, N, P, T, W, and Y can always be covered by multiple copies of any polyomino. Also at inabapuzzle, you can see his room full of puzzles. (also at Naoki Puzzle Lab at Janko, which also has a Nikoli listing).
- Sam Loyd's Domino Puzzle
- David Singmaster - In the Cyclopedia of Puzzles, I've found a number of problems where Loyd doesn't give a solution or his solution is wrong. I'm up to p. 112, the Domino Puzzle. His history of dominoes seems to entirely invented by him, but that's part of the charm of the book. However, he actually gives several problems, but the Answer, on p. 354, only addresses one of the problems - that of getting a game with a maximum amount of scoring. The Answer implies that the game shown had a total score of 200. I'm not a whiz at dominoes, so I haven't yet checked it and Gardner doesn't give this in either volume. But I'm wondering if this has been shown to be maximum? At the end, he asks for a magic square formed from dominoes but he doesn't give one. It's not a problem that I have recorded, but I thought that Lucas gave some examples, but what he has are not quite what I was expecting. Dudeney gives a 6x6 magic square constructed from 18 dominoes (Amusements in Mathematics, no. 406) and this may be what Loyd had in mind. One might get larger orders by using larger domino sets, e.g. the double 9 or the double 12 set. Do you know anything about this? [Ed - Some great questions. Does Loyd have the record play, or is there a better known solution? Let me know.]
- Fair Dice
- Scott Sherman: Inspired by your work on fair dice and Shapeways, where I could create custom dice, I recently took a closer look at what it takes to create fair dice. I discovered several interesting things, summarized at my own fair dice page. I've listed the 25 classes of isohedra with finite sides, with descriptions of the transforms I used to create them. I've coined the term polyisohedron for the generalization of an isohedron where every set of sides has the same relationship to every other set of sides. As a simple example, consider the gyrobifastigium, which has 4 square sides and 4 sides that are equilateral triangles. You can choose pairs consisting of one square and one triangle such that each of the 4 pairs has exactly the same relationship to every other pair of square and triangular sides. You can label each set with a unique number to create a fair die. Modifying a polyisohedron with the proper symmetry maintains its "fairness." This shows that shapes such as teetotums and barrels are fair dice even though they're not isohedra. I've created a bunch of unique fair dice and made them available on Shapeways.
- Polyform Blog
- Alexandre Owen Muniz: I've put some new polyform material on my blog puzzlezapper.com.
- Mathematical Snow Sculptures
- For the 11th straight year, Stan Wagon has entered the Breckenridge Snow Sculpture competition.
- Finite Geometry Models and Videos
- Burkard Polster has put some of his movies on the Smallest Projective Space online. He's also put up some PG(3,2) models on Shapeways.
- Political Subversion
- Start with the letters POLITICAL SUBVERSION. Remove the letters APT. Rearrange the remaining letters to get a famous politician currently under investigation. Also odd: Barack Hussein Obama - Hosni Mubarak = casabe (a type of flatbread).
- The Onion's article on Obamastroid has some nice satire.
- A Balanced American Flag
- George Sicherman has added some balance.
- Age of Puzzles
- The blog of the Grabarchuk family, Age of Puzzles, has a lot of new puzzle content.
- OEIS.org Looking For Donations
- I've joined among the donors to the OEIS Foundation. The Online Encyclopedia of Integer Sequences is incredibly handy for investigating mathematical patters, so please consider supporting it if you can.
- State of Play, and Écarté
- A gaming blog by Thomas McDonald, State of Play, is quite good. He recently used his Kindle to research the obsolete card game Écarté for Games Magazine. I mentioned a few months ago that I was listening to the works of Balzac, Baum, Chesterton, Conrad, Cooper, Crane, Dickens, Doyle, Dunsany, Dumas, Futrelle, Garrett, Haggard, Howard, Hugo, Kipling, Lang, London, Melville, Piper, Scott, Shaw, Shakespeare, Sinclair, Stevensen, Tolstoy, Twain, Verne, Wells, and Wilde -- my list of authors is longer now. Click on any of those links to look at the indexpage picture list I've compiled. Anyway, authors that talked about Écarté, and the number of times they mentioned it, are in the following list. Considering the pedigree of its fans, the game has had an amazing fall from grace.
32 William Makepeace Thackeray
13 Honoré de Balzac
9 Arthur Conan Doyle
7 Anthony Trollope
3 Émile Zola, Charles Dickens, Edgar Allan Poe, Guy de Maupassant
2 G. A. Henty, Ivan Turgenev, Elizabeth Gaskell, Alexandre Dumas, George Bernard Shaw, Joseph Conrad, Wilkie Collins,
1 Percy Shelley, Oscar Wilde, Mark Twain, Howard Pyle, John Galsworthy, L. Frank Baum, Robert Louis Stevenson, and Washington Irving.
- Digits in a Box
- Eric Harshbarger, who is willing to make a custom Lexomino puzzle based on your name, has recently gotten Digits in a Box mass produced. It's the digits 0-9 as polycubes, and you fit them into a box, or other shapes.
- Math Magic Updates
- Erich Friedman, who runs the excellent Math Magic, let me know that Maurizio Morandi recently set a slew of new packing records. For example, squares with area 1 to 16 can be packed into a square with side 12. I also greatly like all the solutions given in the Two Polyform Packing page.
- Tilings of Hyperbolic Space
- Vladimir Bulatov: I though it is appropriate to share the slides of my recent talk "Tilings of the hyperbolic space and their visualization". I work with tiling by Coxeter polyhedra, which are simple looking and limiter in variety in the euclidean space. In the hyperbolic case the tilings exhibit wide variety of shapes and properties. [Ed - Wow, wow, wow. Gorgeous.]
- Fractal Structure of the Partition Function
- No spiffy pictures yet, but the Partition Function has now been shown to have a fractal structure, as shown by research led by Ken Ono. aimath.org has some description and two papers.
- Ljubljana Graph
- Artist Teja Krasek, from Ljubljana, sent me the below look of the Ljubljana graph (which was found by graph theorists in Ljubljana), from her home in Ljubljana.
- John Herivel passes
- John Herivel, who has died aged 92, was one of the leading Bletchley Park codebreakers working on the German Enigma machine cipher during the Second World War.
- Golden Pyramids
- Jacques Ferroul has put together an interesting page on the Golden Pyramids (in French).
- Lots of Data
- For data analysts, Boingboing has released an eleven year archive. If that's not enough, you can look at all the wikipedia traffic. For more, you can also peruse the Google Ngram Viewer.
- Aspen High School
- One of the older online high school and GED prep websites, My-GED.com offers an online high school diploma class which covers basic subjects including Math.
Material added 14 January 2011
- Geomagic Squares
- Lee Sallows has put together a wonderful site of Geomagic Squares. As an example, put 16 hexominoes and heptominoes in a 4x4 square so that the four pieces in any row, column, or diagonal will make a 5x5 square. Or arrange the 12 pentominoes and four tetrominos in the same way for a 4x5 rectangle with a corner missing. Or the below, with 16 hexominoes. A gorgeous presentation.
- Jungle Gym
- I learned that the Jungle Gym was a creation aimed at kids exploring 3D space. The jungle gym was first developed by a Chicago patent lawyer, Sebastian Hinton, in 1920. I mentioned this to my brother Bill, a Chicago patent lawyer, and he found it quite amusing.
- Puzzle Events Calendar
- Otto Janko: The Puzzle Event Calendar is now online. In short: The puzzle event calendar is intended to be a central repository of all puzzle events worldwide; e.g. World puzzle/sudoku championships, national puzzle/sudoku championships and other puzzle competitions. Associated with the puzzle event calendar is an RSS feed and a mailing list.
- Anagrams of the Year
- At the 2010 Grand Anagrammy Awards, one of my anagrams placed 4th. Here are a few of them.
Italian crime boss = A Sicilian mobster. (Meyran Kraus)
Triple chocolate square = Atherosclerotic plaque. (Ed Pegg Jr)
A nurse's care = Reassurance. (Dharam Khalsa)
Solitary confinement = Myself. No interaction. (Adie Pena)
'The Social Network' = Owner likes to chat. (View)
New Year coming soon = A worsening economy? (Harshal M)
From the year, here are a few of my own anagrams that I really liked.
Lay it on me ~ any ol' time.
Nintendo + Cisco = Disconnection.
Shatner spouts ~ "Phasers to stun."
Science Olympiad = Encyclopediaism.
New Orleans Saints = Winner, last season.
Let's do anti-filibuster ~ leaflet distributions.
International Spy Museum = A Russian employment unit
RNA nucleotidyltransferases = Senior lecturer's fantasyland.
- Some Poker Stuff
- Math is a very important concept to playing poker successfully. While there is a tendency to search for the best poker sites with the most fish, or bonus whore for the best poker bonus online, understanding concepts behind game will increase your ROI more than any other factor.
Martin Gardner celebrates math puzzles and Mathematical Recreations. This site aims to do the same. If you've made a good, new math puzzle, send it to firstname.lastname@example.org. My mail address is Ed Pegg Jr, 1607 Park Haven, Champaign, IL 61820. You can join my moderated recreational mathematics email list at http://groups.yahoo.com/group/mathpuzzle/. My facebook page is at Ed Pegg Jr.