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Travel Straws
Re-usable straws in a little keychain-round container with G4G logo (from 2021 conference that was postponed) on it.
The 14 Two-Color Frieze Symmetries in Mosaic Knitting
Mosaic knitting, a relatively new form of two-color knitting, has become popular because it is easier for the knitter than most traditional forms of color work. The price of this ease is an unusual set of restrictions on color placement for the…
Guess-o-matic
This DIY paper-engineered magic trick performs an astonishing feat of mentalism thanks to a bit of secret mathematics.
StarHex-14: Theo Geerinck's 14 Polystars
14 tiles consisting of hexagons with 0 to 6 equilateral triangles attached on their edges can be cut from card stock provided to solve the large collection of puzzle figures presented. Five colors, each tile shape is unique with one mirror pair.…
I AM THE RHOMBUS
In one package: the strip of triangles and brochure for this new flexagon. The colorfully illustrated brochure will include folding directions, flexing directions, and images of the different possible faces.
14 Blocks
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.
The Accountant
Martin Gardner would sometimes wrap puzzles inside stories he concocted, such as with the book “The Numerology of Dr. Matrix.” The following puts my favorite puzzle in that tradition: The Accountant
by Barney Sperlin
by Barney Sperlin
Walk a Crooked Path
In this puzzle you must find the most crooked path on a board made of squares. Each square is visited at most once, but you need not visit all squares. Your path goes from square to adjacent square, and should have as many 90-degree turns as…
Abstract Photograph - Acura TL
One of my interests is abstract photography, using ordinary photographs as the “paint” and using spatial and mathematical transformations to create an image from one or more sources. One transformation that I’ve been exploring is “Inside Out”, which…
A "Pick a Card" Card
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…
The premise is similar…
Traveling Through the Sierpinski Carpet and Menger Sponge
An ant wants to travel from one corner of the Sierpinski carpet to the opposite corner using the shortest possible route. And his friend, a termite, wants to do the same in the Menger sponge. Can you guide them well?
Rep-Tile Tangram
The gift will be a number of cut-out pages to create a rep-tile tangram: A tangram shape that is made from tangram shapes, that are made from tangram shapes.
The Art of Destroying Flexagons
Destroying flexagons can be fun and artistic! We suggest 4 different ways to artistically destroy flexagons, each with its own merit. Our exchange gift is a set of 4 flexagons strips, one for each demonstration and the attached explanation sheet.
14 Rabbiducks
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…
C.L. Dodgson (Lewis Carroll) Oxford Mathematician
Lewis Carroll, the nom de plume of the Rev. Charles L. Dodgson, a mathematics lecturer at Oxford, was also an innovator in recreational mathematics, magic, puzzles, cryptography, and inventions. His appearances in Scientific American began with…
Leaping Crossword No. 2
A one-page puzzle with attached solution will be provided, including the instructions for this variant and the clues and grid.
Winning Ways HexaFlexagon
Sadly, all within 13 months of each other, the three authors of the iconic book Winning Ways for Your Mathematical Plays passed away.
Elwyn Berlekamp: Sept 6 1940 – Apr 9 2019
Richard Guy – Sept 30 1916 – Mar 9 2020
John Horton Conway: Dec 26 1937 –…
Elwyn Berlekamp: Sept 6 1940 – Apr 9 2019
Richard Guy – Sept 30 1916 – Mar 9 2020
John Horton Conway: Dec 26 1937 –…
4!-Fold 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!
Public Math Postcards
Postcard from Public Math with thought provoking questions.
Sakura Pythagorean Tree
Inspired by the Pythagorean Tree in a plane, I stitched the Sakura Pythagorean Tree on a temari ball of diameter 58 cm. This Pythagorean tree has order five and begins with a square of side 5 cm. Upon the first square I constructed two squares to…
Jerry Slocum Mechanical Puzzle Collection Trihexaflexagon
The item I would like to submit for the G4G14 Gift exchange is a copy of a give-away puzzle, developed by the IU Libraries, to advertise the Jerry Slocum Mechanical Puzzle Collection. This promotional item features a trihexaflexagon and informational…
A Torus Without Diagonals
Cut-and-fold a polyhedron with 7 vertices, 14 faces, 21 edges, and a hole through it like a doughnut. A cube has internal diagonals that connect the diametrically opposite corners. By contrast, this polyhedron has no internal diagonals. There are…
