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A Gift of the Number 13 for G4G13
Participants will receive one spruce cone along with instructions on how to read the number 13 in it.
The X-Y Chart
My gift exchange item is called an X-Y Chart. It is a very unique chart of multiplication facts for elementary school students. My friend, Joe Speier, who was concerned about children learning their multiplication facts designed the chart. During a…
Multimodular Origami: A Truncated Icosahedron
This document contains original diagrams and instructions for making a truncated icosahedron (Buckyball) using hexagon and hexagon/pentagon strip modules designed by the author.
13 Serpentine Symmetries
A full-color printed card showing and explaining Serpentine Symmetries, a beaded jewelry set that illustrates the 13 wallpaper groups compatible with bead crochet rope. Serpentine Symmetries was part of the 2018 Joint Mathematics Meetings Exhibition…
Poly-Twostors Periodic Table, Catalog of 3D Printer Models
It is a classification of 3D Tori. This catalog consists of 14 page which lists the Poly-Twistor models updated in January 2018.
PiTop
Pi is certainly one of the most important numbers in mathematics, physics, engineering and, indeed, in all scientific and even some artistic subjects. I have developed a new object which makes Pi tangible in novel tactile, acoustic and visual ways.…
Mental Factoring Cheat Sheet
This is a summary of mental factoring, the essential information condensed into two pages.
Nontransitive Dice for Three Players
With nontransitive dice you can always pick a dice with a better chance of winning than your opponent. There are well known sets of three or sets of four nontransitive dice. Here we explore designing a set of nontransitive dice that allows the player…
Money From Nothing: Or Why the Serial Number Now Appears Twice on Each Piece of Currency
Martin Gardner introduced me to Vanishing Area Paradox Puzzles in Aha! Gotcha! with the Vanishing Leprechaun Puzzle. He explained the paradox by describing an old counterfeiting method. I've learned the method and so I'm going to share it with you.…
G4G13 Clock Face
A clock face showing the logo for G4Gn at the nth hour, for n=5-12, and the G4G13 logo in the center, and miscellaneous MG items for hours1-4.
How Safe Is It?
A spectator, with good arithmetical abilities, opens an invisible safe and deposits some invisible coins in it. The magician has the spectator do some arithmetic, receives the final result and then correctly opens the safe and retrieves the correct…
Cause to Wonder
A lighting fast calculation trick- good for the not brilliant to seem brilliant and the youngster to be motivated to mentally calculate. It will be printed on paper and I will bring it with me.
Postcard and Tiny Piece of Equilateral Tridecagon Tiling
I prepared postcards and tiny pieces of "Equilateral Tridecagon Tiling" for the Gift Exchange.
G4G13 Latin Square Puzzles
A small collection of Latin square themed puzzles created in honor of the G4G13 conference.
A Fair Die of 13 Faces
A cube is used as a fair die of 6 faces. However, there are many dice of different shapes on the market. To make them fair, most of them usually have some symmetric shapes. I classify these variants of dice on the market into two groups. First, let's…
G4G13 Logo Design
This configuration of thirteen sets of concentric circles grows out of an ancient tradition of visual alchemy. The faculties of imagination and intuition are employed as guides in the discovery of new and meaningful relationships between geometric…
Spectrominoes
This is a paper version of a domino game based on the color addition rules of Al-Jabar designed by Robert Schneider.
Laser Cut Pythagorean Theorem Puzzle
A laser-cut puzzle that illustrates a proof of Pythagoras’ theorem. The puzzle pieces either fit in 2 squares aXa and bXb, or in a hypotenuse square cXc. The shapes in the puzzle are taken from a known proof of Pythagoras’ theorem. To my surprise the…
12...N Polygons for Plane Tiling
I made pentagons of edges whose lengths are 1,2,3,4 and 5 in order and can be tiled the flat infinitive plane. And also hexagons of 1,2,3,4,5,6 edge length. A set of a few of them is my exchange puzzle.
1 to 8 Squared
A polyomino packing puzzle with 8 pieces ranging in size from 1 to 8. The main goal is to create a 6x6 square. Further goal shapes (and solutions) can be found on https://www.jaapsch.net/g4g/g4g13.htm
Tensegritiy Pop-up
In each envelope there will be Kenneth Snelson-like tensegrity flattened inside. As you pull it out, it will pop up to a 3D sculpture.
Motley Cube
Six identical sheets to cut out and assemble to make a colorful transparent model of a Motley Cube - a cube dissected into the minimum number of rectangular blocks such that no two blocks are both bounded by the same two parallel planes. In other…