Surprise! Puzzles
Puzzle, Word Play
A small booklet of 20 math puzzles that involve the element of surprise. Some appear to lack sufficient information to solve; others run counter to one's intuition as to what the answer should be.
G4G13
Dick Hess
G13-079
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
Type 14 Tessellating Pentagon
Puzzle
Art
Toy
This item for the Gift Exchange is a 3D printed baker's dozen of irregular pentagons that tessellate the plane.
Rolf Stein
G4G13
Laura Taalman
G13-031
Rubik's Crew - Pinkie Pie
Puzzle
My Little Pony, 2x2, Rubiks Cube
G4G13
Tanya Thompson
G13-069
Lights & Spheres
Art
Toy
Science
A 7cm green plastic sphere with a surface of conical projections, otherwise known as a Cando Massage Ball.
Titanium LED keychain flashlights: I will ship 200 with white LED, 100 with red, blue and green LEDs. Each attendee will receive one light with white LED, and one light with either blue, red or green LED.
G4G13
Stephen Turner
G13-050
Cavalieri Content Cups
Art
Recreational Math
Just as 13 breaks up nicely as the sum of 8 and 5, so too does the (volume of a) cylinder break up nicely as the sum of a cone and hemisphere, a fact we have seen demonstrated at previous Gatherings in vivid ways. But the one-diagram proof of this partition using Cavalieri's principle is remarkably flexible, as the non-standard Cavalieri Content Cups to be distributed will show. For more information, see v.gd/stinf.
G4G13
Glen Whitney
G13-048
Pattern Stacker
Puzzle
Art
An abstract spatial thinking pattern puzzle
G4G13
Alison Yada
G13-064
Build 14 Bridges
Puzzle
Game
Recreational Math
The puzzle is strongly related to the number 14.
The trick is based on a pythagorean triple.
The size of the puzzle is about 10cmx10cmx2.5cm, and it is made by MDF.
Goal: Put all bridges on the board.
G4G14
Ryuhei Uehara
Tomoko Taniguchi
G14-021
Modular Space-Filling Tetradecahedra
Puzzle
Art
Recreational Math
This Gift Exchange item will consist of four flat pre-cut polyethylene sheets that can be assembled to produce two truncated octahedra with connectors for interlocking into the space-filling arrangement of copies of this polyhedron. Multiple participants can combine their items to produce large three-dimensional structures.
G4G14
Glen Whitney
G14-034
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