(Phi)ve is a Magic Number
Math
James Joseph Solberg
G4G13 Gift Exchange Book
G13-P045
1 to 8 Squared
Puzzle
Rec Math
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
G4G13
Jaap Scherphuis
public
G13-018
12...N Polygons for Plane Tiling
Puzzle
Rec Math
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.
G4G13
Yoshiyuki Kotani
public
G13-019
13 Parallels between Martin Gardner and Stan Freberg
Legacy
John Edward Miller
G4G13 Gift Exchange Book
G13-P046
13 Serpentine Symmetries
Art
Rec Math
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 of Mathematical Art, and is one of many complete symmetry samplers in fiber arts that will appear in my G4G13 talk.
G4G13
Susan Goldstine
public
G13-072
13 Sided and Suits Dice
Game
Game, Toy, Rec Math
This pair of unique dice consists of a 13-sided die with both numbers and face-card labels for J, Q, K, and A, along with a 4-sided die with the standard playing card suits.
G4G13
Robert Fathauer
Henry Segerman
public
G13-082
14 Blocks
Puzzle
All you have to do is move the large 2x2 block to the bottom right hand corner by sliding the blocks. Do not lift, turn or twist any block.
G4G14
Marti Reis
G14-044
14 Rabbiducks
Puzzle
Recreational Math
The puzzle is to fit 14 “rabbiduck” polyomino pieces into an 8x11 rectangle. (Gardner wrote about polyominoes in multiple columns. The specific polyomino pieces used are inspired by the rabbit/duck illusion that Gardner called the Rabbitduck in his autobiography.)
14 “Rabbiduck” Pieces that look (crudely) like a rabbit or a duck depending on orientation.
G4G14
Haym Hirsh
G14-055
14 Rabbiducks
Puzzles
Haym Hirsh
G4G14 Gift Exchange Book
G14-P051
14-sided and Skew 8-sided Dice
Toy
Recreational Math
A fair 14-sided die in the form of a heptagonal trapezohedron and a fair 8-sided die ("Skew d8") in the form of a triangular dihedron.
Dice Lab
G4G14
Robert Fathauer
Henry Segerman
G14-031
2184 (Oh, the Absurdity)
Math
Dana Mackenzie
G4G13 Gift Exchange Book
G13-P040
300+ Digits of Pi From an (Almost) Ordinary Deck of Cards
Recreational Mathematics
Michael Keith
G4G14 Gift Exchange Book
G14-P027
4 x 13
Art
The talk corresponding to this paper can be found here: <span><a class="in-cell-link" href="https://www.youtube.com/watch?v=ZijlID83FTg&t=15s" target="_blank" rel="noreferrer noopener">https://www.youtube.com/watch?v=ZijlID83FTg&t=15s</a></span>
Margaret Kepner
G4G13 Gift Exchange Book
G13-P010
4 x 13
Game
Art
Recreational Math
There are 52 cards in a standard deck of playing cards: four suits of 13 cards each. To design a deck of cards, one needs to establish the four suits, each with its own symbol and/or concept, and find a logic for generating the 13 cards in each suit, usually related to the numbers from 1 to 13. My exchange gift is a booklet summarizing my progress to date in designing a set of playing cards based on ideas that Martin Gardner wrote about in his books and columns. The talk corresponding to this item can be found here: <span><a class="in-cell-link" href="https://www.youtube.com/watch?v=ZijlID83FTg&t=15s" target="_blank" rel="noreferrer noopener">https://www.youtube.com/watch?v=ZijlID83FTg&t=15s</a></span>
G4G13
Margaret Kepner
G13-020
4-gons and 13-gons
Art
A circle sticker with an image of a hyperbolic tiling of 4-gons and 13-gons.
G4G13
Roice Nelson
public
G13-053
4!-Fold Puzzle
Puzzle
Are there any polycubes that can be unfolded into exactly a rectangle? This problem was solved in 2019. The smallest solution forms a nice puzzle — fold the rectangle into a polycube!
G4G14
Bob Hearn
G14-061
A "Pick a Card" Card
Magic
Recreational Math
A card (roughly the size of an index card) with an image that contains 54 playing cards (some duplicates, of course!). A spectator chooses one of the playing cards and, after a few questions, the magician reveals the choice!
The premise is similar to the well-known “pick a number” cards where binary representations are used to identify a mystery number that a spectator has chosen. In this case, the spectator will select any card that he/she sees, and indicate the colors of the squares in which this card is found. The magician then reveals the thought-of card!
Instructions will be printed on the back of the card.
G4G14
John Harris
G14-050
A 14 Puzzle for G4G14
Puzzles
Todd Estroff
Jeremiah Farrell
G4G14 Gift Exchange Book
G14-P045
A Card Trick Inspired by Perfect Shuffling
Magic
Steve Butler
G4G13 Gift Exchange Book
G13-P026
A Christmas Card by Leslie E Shader
Puzzles
Soni Shader Huffman
Timothy Huffman
G4G14 Gift Exchange Book
G14-P059
A Collection of Match Stick Puzzles
Puzzle
Game
Every week at my School's math club, we have one puzzle to solve based around match sticks. My gift exchange item will consist of a small booklet containing 21 match stick puzzles ( in honor of Martin Gardner being born on the 21st of October), as well as a collection of match sticks to solve the puzzles with. The match sticks will have the ends cut off so that there is no danger of fire.
G4G13
Nathan Gaby
public
G13-010
A Collection of Open(ish) Problems
Recreational Mathematics
Peter Kagey
G4G14 Gift Exchange Book
G14-P026
A Fair Die of 13 Faces
Art
Rec Math
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 consider that a sphere as a model of a fair die with infinity faces. Based on this model, many symmetric shapes can be modeled as dice obtained by caving spheres. We also have a familiar fair device; a coin. That is, a fair coin can be seen as a fair die with 2 faces. However, a real coin has a thickness, and hence it is, in fact, an unfair die with 3 faces. From this viewpoint, I propose a way for designing a fair die with n faces for arbitrary n. I also prepare fair dice with 13 faces as an exchange gift of G4G13.
G4G13
Ryuhei Uehara
public
G13-035
A Figurative Tree
Art
Artwork of a low-resolution figurative tree.
G4G13
Robert Bosch
public
G13-075
A Flexier Hexaflexagon
Games
Jim Propp
G4G13 Gift Exchange Book
G13-P023