This must surely be the smallest commercially available 3D puzzle cube in the world.
It is a tiny 7.5 mm across and presents a real challenge to solve and take apart - and not just because of its size.
It is an example of a sequentially interlocking cube which means that it won't fall apart once the pieces are slotted together.

You can find many more interlocking puzzle cubes in the microcubology shop.

The puzzle was inspired by the cover of Elbow's brilliant album, The Seldom Seen Kid.

This cube really is something quite special.

About a year ago, after seeing the Transformers movie, I was inspired, by the behaviour of the alien technology in the AllSpark cube, to try and design a puzzle that could expand equally in all directions. To make things even harder, I wanted each piece to be locked in place by the preceding move.

After many prototypes I finally succeeded in creating this unique sculpture consisting of six parts.

The first stage in solving the puzzle involves discovering how the pieces fit together in the expanded configuration. (One of these moves includes a rotation, which makes it much harder to crack by computer!)

The second stage is to collapse the expanded cube down to the smaller cube by pressing each of the faces in the correct sequence.

The name of the puzzle comes from a (now obsolete) alternative to the Big Bang Theory proposed by Fred Hoyle. I like the fact that from its expanded, steady state the cube can either collapse inwards or explode outwards.

© Richard Gain 2008

Inspired by the logo on the cover of Elbow's album, The Seldom Seen Kid, this interlocking 3-piece puzzle is not as easy as it looks. Unlike all my other cubes, which were created in Burr Tools, this puzzle was modelled by hand to give every one of the cubes a bevelled edge. This not only makes it look more like the Elbow logo, it also makes the puzzle even trickier to take apart.

This is the first interlocking cube I ever designed. It consists of four pieces which fit together with a series of sliding movements. It is not too difficult for the average puzzler but will provide a satisfying challenge at this small scale. The completed cube is 1.6cm on each side.

Update: Jury 1st Prize winner at the 2011 International Puzzle Design competition

Two open-ended Superstrings with the correct spin can be merged into a super-symmetrical cube.

The idea for this puzzle emerged when I was designing shapes based on two interlocked tetrahedra.  Inspired by ideas from 'string theory' and 'super-symmetry', I began to search for shapes that were both symmetrical and as similar as possible.

Taking the two pieces apart is not too difficult; reassembling them back into a cube can be more challenging. Hold one of the pieces still; move the other piece through the correct sequence of lateral and rotational moves.

Two colour dyed version in a perspex display case available from Etsy.

Reviews of Superstrings by puzzle enthusiasts from around the world.

"Another great little pocket puzzle from Richard Gain" - Allard Walker - Puzzling Times

"I can't really think of any downsides with this one, it was an elegantly designed puzzle that was fun to solve. Well done, Richard!" - Brian Pletcher - Mechanical Puzzles

"An attractive tactile puzzle with a decent challenge but not too awful - a really good addition to my display." - Kevin Sadler - Puzzlemad

"This is a really tough puzzle, and I can see why it won favor with the judges at IPP. Much easier to take apart than it is to put together, Richard can be rightly proud of this one." - Neil Hutchison - Puzzling Parts

OK, I hear you cry, why Tertiary? Whatever happened to Secondary Gain?
Well there is one, but this is just a much better puzzle. It has a level of 9 (5.1.1.2) which is trickier than Primary Gain and is definitely approaching the top end of the range for a 4x4x4 cube. The completed cube is 1.6cm on each side.

This is a very clever puzzle designed by Tom Jolly, who will receive a share of profits from any sales. It has the mechanism of a burr puzzle inside the shape of a 6x6x6 cube. The completed cube is 2.1cm on each side.
© Tom Jolly 2004

This is Quinsequential Gamma (2.4 cm) the third version of the Quinsequential design. Quinsequential Alpha required 9 separate moves before the first piece came free. Quinsequential Beta improved that to 11 moves, and now Quinsequential Gamma is ready for public viewing with a respectable 13 moves for first removal.
As far as I know, this is a record for a 5x5x5 cube, so I am laying down the gauntlet!
I have given the design a nickname of 'The Switch Cube' - you'll understand why when you've solved it!
Available in four sizes to suit all budgets.

This is a brand new two piece interlocking cube puzzle which is my adaption of a design by Bram Cohen. It's an interesting challenge to insinuate the spiral piece into the loopy piece using a sequence of 7 moves (including slides and rotations) until they take the shape of a 4x4x4 cube. A great little puzzle to keep in your pocket and show to puzzlers and non-puzzlers alike.
This puzzle is one of the few that works really successfully when printed in metal.

Quickstep is a brand new puzzle cube from a talented designer who appeared on the scene only 3 months ago but has already been breaking records with his extremely clever puzzles. Jeff was introduced to interlocking cube puzzles earlier this year by Jos Bergmans (another of my favourite designers) when he started working at Google. When I first became interested in interlocking cube puzzles back in the 1980s, Mayer's cube from Pentangle was arguably the best example of the genre and has held its title for many years. It required 7 moves to extract the first piece and then the other five pieces then lifted straight out, giving the puzzle a rank of 7.1.1.1.1. Ever since I began designing my own cubes about 8 years ago I have been aiming to improve on Derek Mayer's record with one of my own puzzles. Jeff's latest design doesn't just beat this record - it smashes it, with an astounding 11 moves for the first piece and then a further 5 for the next piece, 3 for the third, and 3 more for the fourth piece. Jeff has very kindly given me permission to sell this little beauty in the microcubology shop, so to do it justice, I have come up with a new open style which I think you will appreciate. The larger holes mean that the puzzle not only uses less plastic (which makes it cheaper to produce) but also offers interesting views of the inner workings as you solve it.

The Szilassi polyhedron is a seven-sided torus where every face is in contact with all of the other faces, proving that for toroidal topology, 7 different colours are required for a surface map.

This simple little shape is a mathematical curiosity, designed to demonstrate colour printing on the sandstone material. It is also a handy filler for topping those orders up to $25.

PLEASE NOTE:
Following changes to the minimum size requirements for some materials, this model was no longer printable. Consequently, I have now increased the size of the model from 2.5 cm to 4 cm in order to make it printable again.

Buckyballs are molecules of 60 carbon atoms called Buckminsterfullerene.
Metabuckyballs are buckyballs made using metaball modelling software (Blender).

This smaller, fatter version is approx 33mm across and has minimum strut thickness of at least 2 mm is suitable for metal (and possibly glass) printing.

This is Quinsequential Gamma (1.5 cm) the third version of the Quinsequential design. Quinsequential Alpha required 9 separate moves before the first piece came free. Quinsequential Beta improved that to 11 moves, and now Quinsequential Gamma is ready for public viewing with a respectable 13 moves for first removal.
As far as I know, this is a record for a 5x5x5 cube, so I am laying down the gauntlet!
I have given the design a nickname of 'The Switch Cube' - you'll understand why when you've solved it!
Available in four sizes to suit all budgets.
Please note that this tiny version will require the use of tweezers.

Here is an experimental smaller version of the popular Steady State cube based on 3mm unit cubes.

In White Strong & Flexible it works well and looks really great when the pieces are dyed in different colours.

Shapeways successfully printed this in metal for me but the roughness of the metal surfaces made it impossible to fit the pieces together at first. After some careful Dremel work all of the surfaces are now smooth and the puzzle can be assembled correctly. However, this did take a significant amount of work and I would not recommend ordering this puzzle in metal unless you are prepared to take on the necessary post-processing work.

Three Easy Pieces is an interlocking 3x3x3 cube puzzle. It's not as difficult as some of the other puzzles I have designed, so if you, or someone you know, is just starting out with collecting puzzle cubes, this may be one for you. The holes are slightly larger to give the best view of the inside as well as the outside of each piece.

Three Tiny Pieces is a 1/2 size version of Three Easy Pieces designed for and tested with Frosted Detail material. It works beautifully.

Copyright - Richard Gain 2011.

This difficult 6 piece interlocking cube puzzle was 3D printed in strong, white nylon and then each piece has been hand-dyed and individually worked to ensure a smooth action. 
Assembling and disassembling this puzzle requires a precise sequence of 14 movements including sliding moves and rotations. The finished cube is 3.2 cm across.

Start with the closed loop and try inserting the H-shaped crossbar into it. Not as easy as you might think, but there is a clue in the name. Make sure you get it the right way round and then the other four pieces should fit in to make a 4x4x4 cube. 
Watch out for a couple of sneaky rotations too.

Using the name of the puzzle as inspiration, and the obvious link to a circus, I coloured alternating pieces red and yellow in the order that the cube is assembled and disassembled. Just another little clue to help you solve this fiendish puzzle.

This is my newest and most difficult design and probably the one I am most proud of. Jos Bergmans called it "Very, very good, a total delight." 

Buying a copy of this puzzle entitles the owner to access a secret video on YouTube providing the full solution.

Copyright Richard Gain - 2011.

These three identical pieces can be interlocked to form a 4x4x4 cube either in 6 sequential steps or smooth coordinate motion. This original puzzle has a beautiful rotational symmetry and is not trivial to solve.
Based on inspiration from Robert Reid's cubic trisections, Tom Jolly's Tangler Puzzle and help from Bram Cohen.
If you would like to get a tri-colour version like the one in the picture, you will need to order three individual copies of "Triaxial piece (2cm)" and specify a different material for each piece.

Quaturnery Qube is my fourth 4x4x4 cube puzzle design and has four pieces.  It has a unique level 4.3.4  solution that includes one rotation. 

The original version of this puzzle came out back in September 2010 in an experimental new hollow cube format and although it sold a few copies, I had hoped it would achieve a wider audience.

So here, in the best traditions of microcubology, is the 2cm version in solid form. This is half the size of the original Quaturnery Qube (one eighth of the volume) and is now quite a bit cheaper.

It's a great little puzzle with a tricky solution and some nice moves. Have fun!

The solution on YouTube was recorded using the original larger puzzle and is rather obscured by my inability to keep the cube in front of the camera as I struggled to work it out (but maybe that's not such a bad thing - I wouldn't want to make it too easy for you).

Micro version of Happiness #20

This is Quinsequential Gamma (3 cm) the third version of the Quinsequential design. Quinsequential Alpha required 9 separate moves before the first piece came free. Quinsequential Beta improved that to 11 moves, and now Quinsequential Gamma is ready for public viewing with a respectable 13 moves for first removal.
As far as I know, this is a record for a 5x5x5 cube, so I am laying down the gauntlet!
I have given the design a nickname of 'The Switch Cube' - you'll understand why when you've solved it!
Available in four sizes to suit all budgets.

 This superb puzzle designed by Jos Bergmans exemplifies everything that I love about interlocking cubes. We share a passion for complex 4x4x4 designs, and Jos, like Tom Jolly, has a real talent for inventing puzzles with clever solutions.

In Jos' own words:
  "There is bunch of engineers at my office that are totally into puzzles, so I give them the puzzle pieces and they try to assemble it. The key measurement here is time: how long does it take them on average to solve the puzzle. When I started out designing (Four Critters, Six Spoons etc), it took them just a minute or two to solve a puzzle. That is when I discovered Tom Jolly's puzzles (it does not get any better than "Twist The Night Away"). Adding rotations to my designs made the puzzles more complex, and it took my colleagues longer and longer to solve the puzzles. 
Currently, a puzzle like "Pivot" can keep them busy for about 40 minutes on average. This solve-time competition keeps me on the edge, and pushes me to find new ways of making the puzzle more difficult."
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This puzzle is the first in a new larger format based on 8 mm unit cubes giving a 3.2 cm solved cube. The interior of each piece is hollow but the pieces still feel strong and handle well. If the pieces had been solid a puzzle of this size would cost over $50 to print.

I have started experimenting with dyeing my puzzles and, as you can see, the tests went well. If you would be interested in receiving a pre-built and dyed version of this puzzle, or any of my other cubes, please visit the main shop page and use the 'Send message' link  under microcubology logo.

A new 4x4x4 interlocking puzzle cube designed by Jeff Namkung. This complex puzzle requires a sequence of 9 moves to get the first piece out which is a new world record for solid faced 4x4x4 interlocking cubes. This is a great puzzle that prints beautifully in this larger, 4 cm size and should be solvable by any good puzzler. It took me about 15 minutes to find the solution (without cheating and using a computer). If you like this one, you might also like to have a look at Bolero by Jeff Namkung. It has one less move for first piece removal but is significant harder.

The Triaxial Cube puzzle consists of three identical pieces. This single piece is designed for the White Strong and Flexible material.
You will need to order three of these pieces to make the puzzle. Having the puzzle available as a single part allows shoppers to order each part in a different colour (Limestone, Blue Jeans and Terracotta) if desired.

I am delighted to be able to present one of the most original interlocking cube puzzles to be designed for many years. Once again, Tom Jolly has kindly given his permission for for this design to be made available through the microcubology shop.

The solution is described as requiring 20 moves (1-2-3-12-2). However, the most unusual feature of this puzzle is the sequence of seven rotations required in the middle of the solution.

The puzzle design can be viewed at http://bit.ly/cvsxev , and although it can be constructed from a set of LiveCubes, the rotations involved can make the pieces break apart rather easily.

This version of the cube has a width of 2.4 cm which, although making it a little more expensive, gives it a decent weight and excellent strength.

You can read more about this puzzle in Brian's (excellent) Damn Puzzle Blog at http://mechanical-puzzles.blogspot.com/2010/06/twist-night-away.html

A serially interlocking 3x3x3 cube made from springy cubelets.
Perfect snug fit every time. Not too difficult to solve.
Original puzzle design by Stewart Coffin.

This little beauty is another classic Jos Bergmans 4x4x4 interlocking puzzle cube. It's the first puzzle by Jos that I tried and it's definitely still one of my favourites. The difficulty level is 1.2.5.3.2 (one move to get the first piece out, two for the second, five for the third and so on) but includes rotations.

This puzzle consists of six pieces including a couple of unusual ones. The largest piece looks like an almost complete loop bent to 90 degrees in the middle. Clearly some of the other pieces will have to go through this loop. The second largest piece has a long shaft with a square block at one end and a larger L shaped block at the other end. This is the elevator. I would love to show you how this puzzle works but that would spoil the delicious 'aha' moment you'll get when you work out how everything fits together.

My hollow design is based once again on 8mm unit cubes giving a 3.2 cm puzzle. The fit is snug to begin with but will loosen a little with use to the point where it should just hold together nicely.

Buying a copy of this puzzle entitles the owner to access a secret video on YouTube providing the full solution.

Model developed by Richard Gain. Puzzle designed and licensed by Jos Bergmans (2010).