Rubik's Cube

43,252,003,274,489,856,000 permutations

The idea of building a working Rubik Cube has always appealed. Here the challenge is to create a mechanical device that has a number of degrees of freedom about a central point. It's not easy! The cube consists of 12 edge pieces, 8 corner pieces and one central piece. All of these have to be interlocking, yet still be able to rotate about any axis at any time in any direction! And all this with a basic square block! Thankfully LEGO has been kind and the ratio of 5 bricks to 6 studs allows us to create a genuine cube structure.
I must point out that quite independently a fellow LEGO enthusiast has also constructed a working Rubik's cube. Maarten Steurbaut's cube is quite a bit different from mine. His original design is based around 8x8x8 cubes and so it's slightly larger than my cube. After seeing my version Maarten went on to create a Rubik's cube that's smaller than my one based on 4x4x4 cubes. The challenge now is to get proper corner pieces into the 4x4x4 version.
Rather than boring you with endless detail of how a Rubik Cube works it's probably better just to scroll down or use the links to jump to a specified sections and see how it was constructed. There's even a movie of the Rubik's cube in action - its operation is a bit sticky due to there being slightly different levels between pieces (a result of not having enough tile plates), and self-destruction was always a possibility!
Inside a Rubik's cube is a mechanism that has six stems coming from the centre. Each of these stems a centre piece is attached. These pieces can rotate with the stem being their axis of rotation. T
The edge pieces have to lock between two of the centre pieces, but allow the corner pieces to slide past them when one face is being rotated. There are twelve edge pieces in total.
A Rubik's cube has eight corner pieces. These were the most difficult part to make since the square nature of the LEGO brick doesn't lend itself too well to the creating circles. The corner pieces have to move completely round the entire cube as well as ensuring the whole puzzle remains self-interlocking (ie. it doesn't fall apart).
There are four photographs of the whole Rubik cube. Three are the basic LEGO model and the fourth has the stickers attached. The whole cube was pretty big, which meant trying to do it very difficult. In fact the whole model was prone to self-destructing, something that could only really be solved by using glue. I also didn't have enough tile pieces. The consequence of this can be seen in the movie of the cube in action. Basically, it meant that some of the centre and edge pieces had at fractionally different heights than their neighbours, resulting pieces catching when rotating. For completeness I've also added a few photos of the cube being constructed.
There are a LDRAW CADs for the different parts and step-by-step instructions on how to build it.