### Impossible Bolt

Only available from these aritist/craftsmen:

From Etsy: **BUY NOW: Impossible Bolt & Nuts**

Impossible Bolt: one nut threads on clockwise as normal- the other threads on counterclockwise on the same bolt! Not impossible- but carefully engineered and machined. Swipe for partial hint on mechanism. This puzzling curiosity was inverted by Scott Eliott and machined in solid brass by puzzle crafters Steve Nicholls and Ali Morris of TwoBrassMonkeys.

### Poly Density Puzzle

Get the kit here:

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

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 Arrow

One of many creative illusions and curiosities of Victoria Skye. See her work here:

**Visit Now: Victoria's Illusion Art**

Click here for to explore more **"impossible objects"**

Impossible Arrow: an arrow made of wood through the center of standard steel hex nut. The arrow was carved and somehow placed through the nut- neither the wood nor the steel nut was cut or glued to produce this object. Not impossible, but creating this does depend on the use of some obscure physical properties of wood (similar to the impossible nail sculpture).

### 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

### Nova Plexus Tensegrity Puzzle

Precisions machined and available in brass or stainless steel:

From Art of Play: **BUY NOW: Nova Plexus Puzzle**

Nova Plexus Puzzle: 12 identical brass rods can create 4 interlocking triangles in a perfect symmetry- look carefully and you can see that each rod is in an identical configuration with the 5 others that connect with it. Precision machined notches on the ends of the rods allow them to interlock with elastic tension such that vector sum of the 5 forces on each rod is zero- creating this astonishing geometry as the equilibrium state. Unlock the ends of any two rods and the system instantly disassembles (swipe to view process in slow motion). Invented/designed by artist and computer scientist Geoff Wyvill in 1978, this puzzle has just recently been made available for sale with a limited production run.

### 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.

### Mirror Vision Puzzle

More than three versions of this puzzle out there. Get one here:

From Amazon: **BUY NOW: MIrror Vision Puzzle**

From eBay: **BUY NOW: Mirror Vision Puzzle**

Mirror Vision Puzzle: this Harry Potter themed puzzle has only 9 pieces but each supplies two parts of the final image- without the mirror one gets only half the picture. The top of each square is a corrugated lenticular composition of two images, and when viewed from the correct angle only one image can be seen directly, with the other reflected in the mirror, which combine in this case to reveal the famous phoenix bird of the HP stories. Flipping over the puzzle squares produces a second image to solve, this time a basilisk. An ingenious puzzle form from inventor/designer Mark Setteducati and sold by Mattel.

### Hydrophobic Water Maze

Wonderfully well crafted and available from this shop :

From Etsy store TheSmallestWorkshop:

**BUY NOW Hydrophobic Water Maze**

Hydrophobic Water Maze: a superhydrophobic coating allows this dynamic puzzle to use a drop of water as the "pinball", which can split into multiple smaller drops and recombine along the way. The wood surface is treated with silica nano-coating that makes water roll off- a condition sometimes referred to as the Lotus effect because leaves of the Lotus plant have this property.

### 10 Hex Puzzle

This and other beautiful and well made puzzles are available on Etsy:

From Etsy: **BUY NOW 10 Hex Puzzle **

Two great resources about these polyhexs: polyform puzzler page and puzzleworld page

10 Hex Puzzle: this puzzle is comprised of pieces which are the set of all ways three and four hexagons can be joined with a common edge. There are 3 trihexs and 7 possible tetrahexs, and similar to pentominoes, these 10 polyhexs can assemble into a large hexagon. Amazingly there are exactly 12,290 solutions to this puzzle- but it’s still a challenge to find just one!

### Rhombic Blocks Mathematical Puzzle

This beautifully made puzzle available here::

From Etsy: **BUY NOW **

Rhombic Blocks

Rhombic Blocks Mathematical Puzzle: There are 9 possible ways three rhombuses can be joined together along a common edge, and similar to pentominoes, these 9 tri-rhombs can tile a polyhedron, in this case a hexagon. There are 14 solutions to this puzzle, and one where no same-colored pieces touch. A beautiful math discovery by puzzle master Stuart Coffin.

### Cone of Apollonius

Similar models available here:

From Amazon: **BUY NOW: Cone of Apollonius**

From Etsy: **BUY NOW: Cone of Apollonius**

Cone of Apollonius: Slicing a cone with a plane will produce the famous curves known as the conic sections, as demonstrated with this beautiful vintage wood model by Nasco. Slicing at a right angle to the cone’s axis of symmetry produces a circle, and tilting the intersecting plane a bit produces an ellipse. When the plane is tilted parallel to the side of the cone the curve produced is a parabola, and tilting even further creates a hyperbola. The discovery of the mathematics demonstrated here are attributed to Apollonius of Perga from about 250 BC- thousands of years later Kepler, Newton, and others showed these conic sections to be intricately connected to many branches of physics such as planetary orbits and the optics of telescopes.

### Uphill Roller

This set available here:

From Amazon: **BUY NOW: Uphill Roller Double Cone**

Uphill Roller: a double cone (like two funnels connect by their tops) will roll up a set of inclined rails. Although the bi-cone rolls toward the higher end, its center of mass descends due to the geometry of the rails. This curious construction was first published in 1694 by the noted surveyor William Leybourn to promote “recreation of diverse kinds” towards the “sublime sciences”. Physics fun from three centuries ago!

### Pentominoes

Get this set here:

From Etsy: **BUY NOW Hardwood Pentominoes **

Many versions available here:

From Amazon:** BUY NOW Pentominoes **

The book by mathematician Solomon Golomb that started the polyonomo recreational math craze:

From Amazon: **BUY NOW: Polyominoes **

Pentominoes: The 12 possible arrangements of five identical squares joined edge to edge. Since 5x12=60, the pentominoes can tile a 6 x 10 rectangle with no gaps (2339 ways to do this- yet even finding one solution is a challenge). I love this beautiful set from artist/woodworker Ron Moore where each pentomino is made from a different kind of hard wood.

### Ice Melt Demo

Get this similar demonstration kit here:

From Educational Innovations: ** BUY NOW**

Ice Blocks Melt Demo

Ice Melt Demonstration: Wood or Aluminum- which will melt the ice fastest and why? Both blocks start at the same temperature (room temp) and have the same shape and volume. Swipe to reveal result shown in real time (not sped up!) Hint: Although both blocks are at the same temperature, the aluminum feels cool to the touch and the wood block feels warm. Those who have taken basic physics should have an advantage on this question- one block is an excellent insulator and the other a conductor.

### Impossible Caged Golf Ball

Some nice versions of this impossible object available here:

From Etsy: **BUY NOW: Golf Ball in Wood Cage**

See more of these thought puzzles in my collection here: Impossible Objects

Impossible Caged Golf Ball: Here a regular off-the-shelf golf ball somehow trapped within a cage made from a solid piece of hardwood walnut. Neither the ball nor the wood were cut or glued in the fabrication process. The puzzle aspect is to consider how this object was produced (I have some theories- but I do not know the secrets of this artist).

### Perspective Puzzle

Vintage puzzles in this series are sometimes available on eBay:

From eBay: **Search NOW Virtual Illusion 3D Puzzle **

Perspective Puzzle: ten flat images, when ordered and spaced correctly, combine to produce this 3D illusion of structure and depth. This vintage toy by Mattel was sold as “Virtual Illusion 3D Puzzle” where the challenge is to scramble/shuffle the 12 sheets and then place them in the correct orientation and order to complete the image. A fun application of the math and physics of anamorphosis and perspective.