### Two Marble Puzzle

Similar 4 marble version of this puzzle available here:

From Etsy: **BUY NOW Four Marble Puzzle **

From Amazon:** BUY NOW: Two Marble Puzzle, **or get this** set of puzzles**

Two Marble Puzzle: physics brain teaser- move both marbles to their top locations on each side simultaneously. The solution to this puzzle relies on some fun basic physics principles- can you figure out which ones? Swipe to reveal solution. Found this well made version of this classic physics puzzle at a gift shop in San Francisco (note Golden Gate Bridge motif).

### Ring Catch Chain Trick

Get a set here:

From eBay:(best selecton)** BUY NOW Ring Chain Catch**

From Amazon:** BUY NOW Ring and Chain Set **

The physics of this trick in great detail with more slow motion: Ring Falling into a Chain: No Magic — Just Physics

Ring Catch Chain Trick: a solid ring will be caught by a loop of chain if it tumbles during its fall. By Newton's Third law, when the ring twists into and hits the chain, the impact transfers momentum to the end of the chain, which rises up and over the ring- seen here in 480 fps slow motion.

### Four Marble Puzzle

Get this well crafted puzzle from Creative Crafthouse here:

From Amazon: **BUY NOW Crossroads Four Marble Puzzle **

From Etsy: **BUY NOW Four Marble Puzzle **

Four Marble Puzzle: physics brain teaser- move all four marbles to their corner locations simultaneously. Each slot slopes down towards the center such that the marbles tend to stay at the center- so, how would one get them to roll outward at the same time? The solution to this puzzle (like others featured here) relies on some fun basic physics principles. Answer below and swipe to reveal solution. A beautiful and well-made puzzle from Creative Crafthouse.

### Matsuyama's Paradox

Get this and other amazing math puzzles here:

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

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.

### TrueBalance

Get the full version (8 disks made of wood) or the mini (6 disks, blue or red plastic):

From Amazon: **BUY NOW TrueBalance Coordination Puzzle **

TrueBalance: coordination challenge puzzle- get the six disks, connected by bearing swivels, into a vertical stack by only tilting the handle. Harder than it looks to get each disk’s center of mass above the one below at the same time into the unstable equilibrium final state. The swivels constrain the system, limiting the degrees of freedom, and allowing strange and interesting motion. Kinetic art as a toy!

### Aristotle's Wheel Paradox

Get this demonstration puzzle here:

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

WIkipedia has some details on the Wheel "Paradox"

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?

### Soma Cube

The Soma Cube is available in a variety of materials and colors:

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

From Etsy: **BUY NOW: Soma Cube**

Soma Cube: Math toy 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 (yes- that 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. Amazingly there are 240 ways to make the larger cube from these 7 pieces- still not that easy!

### Raketti Puzzle

Versions of this puzzle avaioable fron these sources:

From CuriosityBox: **BUY NOW Raketti Physics Brain Teaser**

From Etsy: **BUY NOW Raketti Physics Puzzle **

Raketti Puzzle: physics brain teaser- the challenge is to remove the cone topped cylinder from the hole without touching the bottom container (no fair using sticky tape or such). It can be done in a matter of seconds! The solution to this puzzle (like others featured here) relies on some fun physics principles.

### 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**

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).

### Penrose Aperiodic Rhombs

This set avaiable here:

From : **Search NOW Penrose P3 Tiling**

Wikipedia has the details on Penrose Tilings and their inventor Sir Roger Penrose (Recently won Nobel Prize!)

Another nice version of Penrose Tilings is available here:

From Etsy:** BUY NOW Penrose Tiles **

Penrose Aperiodic Rhombs: a famous aperiodic tiling with just two shapes- a pair of rhombuses with equal sides, but with the ratio of their areas made to equal the golden ratio. Note that although the starting pattern of 10 tiles is symmetrical, adding any further tiles breaks the symmetry, as highlighted by the path of the double curves. Sir Roger Penrose- who just won the Nobel prize in physics for his contributions to General Relativity- also discovered tessellations (tilings) that are aperiodic even though the two tile types are regularly shaped polygons. If one tries to shift a part of a Penrose tiling, the shifted part will not align or match up with any other part of the same tiling- all the way out to infinity! In this construction, single and double line patterns must align such that the tiles can only connect in specific ways to ensure the non-repetitive nature of the Penrose tiling structure. Shown here is one way these two tile types will fill the plane.

### Impossible Wallet

Available here:

From Amazon: **BUY NOW Magic Wallet **

From eBay: **BUY NOW Magic Wallet**

Impossible Wallet: this pocketbook has a special double hinge that allows the wallet to be opened from either side, and leads to some rather nonintuitive consequences. Note that once inserted, the bill shows the same face independent of which way the wallet is opened. The construction of this magic (or flip) wallet is similar to the famous Jacob's Ladder toy.

### Impossible Dovetail

Inexpensive versions of this "impossible box" like that in the video avaiable here:

From Amazon: **BUY NOW: Impossible Box Puzzle**

Impossible Dovetail: this impossible object is pretty common, but it is a classic, and included in my collection. If one assumes a regular dovetail joint then this construction would indeed seem impossible without cutting and gluing, but what one sees from the sides makes for misleading assumptions as this box opens easily. Swipe for reveal once you’ve thought about about possible constructions.

### Impossible Jar with Golf Ball

Get this "impossible" jar and other amazing things from this shop:

From Etsy: **BUY NOW: Impossible Jar & Golf Ball**

Impossible Jar with Golf Ball: a regular off the shelf golf ball somehow trapped within a standard glass jar. Neither the ball nor the jar were cut or glued in the fabrication process. The puzzle aspect is to consider how this object was produced (again, I have some theories- but I do not know the secrets of this artist). This incredible piece was made by craftsman and artist Nathan Nickerson, and comes with the golf tee display stand (a nice touch!)

### Ambiguous Superhero Object

### Poly Density Puzzle

Get the kit here:

From Educational Innovations: **BUY NOW Polydensity Bottle Kit **

Folow the link above for details of the physics explanation.

Poly Density Puzzle: my favorite science brain teaser- white beads and blue beads "float" oddly separated beneath the surface of a clear liquid. If the contents are mixed by shaking the container, the white beads gather at the top and the blue sink to bottom! Adding to the mystery; after about 30 seconds the two layers of beads will have slowly moved back to the middle. What is your guess as to the physics behind this behavior?

### Impossible Bottle Sculpture Puzzle

Mr. Evans makes a variety of amazing impossible bottle sculptures:

From impossiblebottle.co.uk: **Buy NOW Impossible Bottles by Philip Evans **

Nice Impossible bottles are often available on Etsy:

From Etsy:** BUY NOW Impossible Bottles**

Impossible Bottle Sculpture Puzzle: seemingly impossible, but created with clever engineering, this “impossible” bottle contains a padlock and full deck of cards still in the wrapper (a cut out in the side of the box reveals that all the cards are inside). The puzzle aspect is to consider how the bottle was produced (I personally have some theories- but I do not know the secrets of this artist). I can tell you with high certainty that the bottle was never cut or altered in anyway, and it was not somehow formed around the objects. This bottle by Phil Evans is one of the best I’ve seen.