### Magnetic Soma Cube

Get this inexpensive SomaCube here:

From Amazon: **BUY NOW: Magnetic Soma Cube**

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Magnetic Soma Cube: a new fun variant of the famous math toy invented by Danish scientist and artist Piet Hein, who claimed that this puzzle came to him as he was listening to a lecture on Quantum Mechanics by Werner Heisenberg (yes- that Heisenberg). The seven pieces of this puzzle are all the ways 3 or 4 cubes can be joined such that the piece has at least one inside corner. In this version small magnets are encased in cleverly designed cavities such that they will always flip over to attract a counterpart in another puzzle piece, allowing the puzzle to stick together- or hang from the side of the refrigerator. Amazingly there are 240 ways to make the cube from these 7 pieces- still not that easy!

### Rolling Uphill Illusion

Availabel here:

From Etsy: **BUY NOW: Uphill Ramp Illusion**

or get the 3D print file here:

From Thingverse: **Download Now: Uphill Illusion**

Learn more:** The amazing illusions of Kokichi Sugihara**

See the many other Sugihara Illusions: **in my collection**

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Rolling Uphill Illusion: the ball bearings seemingly roll uphill as if attracted by magnets of some kind. What’s going on? Swipe for reveal as it is truly a matter of perspective. A wonderful take on an illusion invented by Kokichi Sugihara of Meiji University. 3D printed by my good friend @zathras5 (Roger Key) from a file designed by Julian Hardy.

### Repelling Marbles Puzzle

Get this affordable and fun kit here:

From Educational Innovations:** BUY NOW Mystery Marbles Puzzle Kit **

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Mystery Marbles Puzzle: a physics brain teaser (now available as a kit) what's going on here? Three glass marbles can move but stay separated in this liquid filled tube no matter the orientation- why do they not touch? Swipe for reveal of components.

**See also: Poly-acrylamide Polymer Vanishing Act**

### Anti-Gravity Puzzle

This particular puzzle by puzzlab.com is no longer in production.

However (spoiler), it's possible to creat a version of this puzzle with these:

From Educational Innovations:** BUY NOW Growing Spheres **

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"Anti-Gravity" Puzzle: a physics brain teaser- what's the trick here? Four glass marbles can move but stay separated in this liquid filled tube no matter the orientation- why do they not touch?

### Flippe Puzzle Ball

Get this puzzle ball here:

From Etsy:** BUY NOW: Flippe Puzzle Ball**

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Flippe Ball Puzzle: this ball is a puzzle that explodes and flies apart when spun. The puzzle is made of three identical pieces and a ball bearing which mysteriously locks the pieces together only to release them after a period of spinning. The main challenge is to fully explain why this spontaneous disassembly occurs. Swipe to see a slow motion boomerang loop of it coming apart- and how conservation of momentum has the three equal mass pieces on equally spaced trajectories (120°) with the ball bearing remaining stationary at the center. A product of puzzle master George Bell.

### Soma and Rhoma Puzzles

The Rhoma Cube is a vintage item and can sometimes be found on Etsy

Soma Cubes are available in wide viariety:

From Amazon: **BUY NOW: Soma Cube**

From Etsy: **BUY NOW: Rhoma Puzzle**

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SOMA and RHOMA Puzzles: Replace every cube in the Soma puzzle with a rhombohedron to create the Rhoma puzzle- where the seven slanted pieces now make a larger rhombohedron. Here I’ve painted the corresponding Soma and Rhoma pieces to match on these sister puzzles that share identical edge lengths. While there are 240 ways to make the larger cube from the 7 Soma pieces, there is only one solution for the 7 Rhoma pieces. The original Soma Cube is a math toy has an interesting connection to physics- invented by Danish scientist and artist Piet Hein who claimed that this puzzle idea came to him as he was listening to a lecture on Quantum Mechanics by Werner Heisenberg in 1933. The seven pieces are all the ways 3 or 4 cubes can be joined, such that each piece has at least one inside corner.

### Elastic Equilibrium Puzzle

Get this puzzle here:

From Amazon: **BUY NOW: Atomic Cherry Puzzle**

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Elastic Equilibrium Puzzle: six spheres held together by three plastic springs. When assembled each sphere exerts the same force on its four neighboring spheres, producing this equilibrium state only if all six spheres are used to balance all the forces. A fun configuration to analyze in a 1st year physics course- the Atomic Cherry by Brainwright puzzles.

### Trisected Cube

Get this puzzle here:

**BUY NOW: Trisected Cube Puzzle**

This puzzle came in my Curiosity Box subscrition. A great way to start collecting your own physics toys (and other brain food):

From the Vsauce team: **BUY NOW: The Curiosity Box**

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Trisected Cube Puzzle: three identical pieces interlock to form a cube in this ingenious dissection puzzle. The cube is sliced following a helical path along a corner to corner diagonal, creating a smooth disassembly, and a smooth but surprisingly challenging initial reassembly. Invented by Robert Reid and designed by puzzle master Oskar van Deventer.

### Missing Edge Piece Puzzle

Get this puzzle here:

From Etsy: **BUY NOW: Missing Edge Puzzle Card**

See the simiar and amazing:** Matsuyama's Puzzle**

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Missing Edge Piece Puzzle: fun math involved in the design of this puzzle, which illustrates how the concept of area can challenge our intuitions. Swipe to see the similar and amazing Matsuyama’s Paradox puzzle. A precision crafted puzzle by Jeux Efcé game shop.

### Stomachion Puzzle

Get this 3-color laser cut acrylic version here:

From Kadon Enterprises: **BUY NOW: Stomachion Puzzle**

Also a very nice multicolor acyrlic version here:

From Etsy: **BUY NOW: Stomachion Puzzle**

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Learn about the 1998 discovery of the lost writings of Archimedes (and the technology used to recover them) in this TED talk.

Ancient Stomachion Puzzle: the oldest known puzzle, discovered in the writings of the great Greek physicist and mathematician Archimedes from some 2200 years ago. The puzzle is a dissection of a square into 14 polygons, where the areas of each piece are integer multiples of each other (a curious way to slice it up). In 2003 Bill Cutler showed that there are 536 district ways to configure these pieces to make the square (five are shown here), ignoring simple rotations and reflections. Swipe to see the most famous solution, attributed to Archimedes himself, that was found in an ancient manuscript discovered only in 1998- before this date historians knew the name of the puzzle, but no one knew what it looked like. Kate Jones, the maker of this particularly aesthetic version, found that when using only three colors for the polygons, there are only 6 solutions where no two pieces of the same color touch (four solutions shown here).

### Frabjous Geometric Sculpture Puzzle

Get one here- five colors to choose from:

From MoMath: **BUY NOW: Frabjous Sculpture Puzzle**

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Frabjous Geometric Sculpture Puzzle: 30 identical laser cut acrylic pieces interlock into 12 interconnected five point stars (each with a spiral vortex center) in this puzzle based of the Frabjous sculpture by artist and professor of mathematics George Hart (Prof. Hart is now on Instagram, follow him at @george.hart.sculptor to see more of his amazing work.) Note that if one connects the tips of the stars one gets the outline of a dodecahedron, with its 30 edges and 12 sides, and if one considers the face planes of the linked pentagrams the underlying shape is a polyhedron called the “great rhombic triacontahedron”. A year or so ago I got to visit the National Museum of Mathematics in NYC where I bought this puzzle in the @momath1 museum shop. This puzzle was great fun to assemble- buy one to support this inspirational museum, and make a great sculpture for your bookshelf!

### Aristotle's Wheel Paradox

Get this demonstration puzzle here:

From Etsy: **BUY NOW: Aristotle's Wheel**

WIkipedia has some details on the Wheel "Paradox"

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Aristotle’s Wheel “Paradox”: How does the smaller attached disk travel the same length as the larger one if both disks only make one full rotation? Note the shorter path of the smaller disk, if rolled on its own. This beautifully made demonstration depicts an issue of geometry and motion that perplexed the best minds of humanity for 2000 years. The ancients knew the formula for circumference, and C=2πR for the large disk is clearly greater than C=2πr for the smaller- so how could the smaller disk, rotated once, still travel the distance of the larger one if attached? The great Galileo even offered a solution to the problem in his book Two New Sciences, where he approximated the situation as concentric hexagons and considered the limit as the number of sides increased. So what is the best answer to make sense of this situation?

### Matsuyama's Paradox

Get this and other amazing math puzzles here:

From Etsy: **BUY NOW: Missing Square Puzzle**

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Matsuyama’s Paradox: dissect a large square in to four equal quadrilaterals, rotate and reassemble- to find a small square is missing! Where did the additional area come from? Fun math involved in the design of this puzzle, which illustrates how the concept of area can often challenge our intuitions. Swipe to compare the two assemblies. A precision crafted puzzle by Jeux Efcé game shop. Wikipedia has good details: Missing square puzzle.

### RPSLK Dice

These dice are available here:

From Amazon: **BUY NOW: Rock Paper Scissors Lizard Spock Dice**

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RPSLK Dice: the famous Lizard Spock extension to the Rock, Paper, Scissors game expressed on 10 sided dice allowing the study of the non-associative nature of the game (Rock wins Scissors, and Scissors wins Paper, but Rock does not win Paper, etc.), and other interesting math. The original RPS game had three “weapons” and only three rules are needed to play the game. Adding Lizard-Spock makes for 5 gestures, but now 10 rules must be used, including “Spock vaporizes Rock”, “Lizard poisons Spock”, and my favorite “Paper disproves Spock” (swipe to see famous graphic). Interestingly, mathematical analysis shows a similar four weapon game with equal odds of winning is not possible. It was also found that the next possible game with 7 gestures would require 21 rules to play. The Lizard-Spock extension was invented by Sam Kass and Karen Bryla in 2005 and made famous on the sitcom Big Bang Theory.