At first glance, the Rubik's Cube appears to be an impossible creation, as it allows all six sides to be rotated independently from each other. However, there is no magical mystery here, it simply takes clever engineering and thoughtful design to create these contortionist cubes.
Since its invention in 1974, a wide variety of designs have been produced for the Rubik's Cube, ranging from 2 x 2 x 2, to the classic 3 x 3 x 3, even growing as large as 33 x 33 x 33. There have been many variations that play with the shape, size, and complexity of this world-famous puzzle. Yet, despite these variations, the fundamental structure remains the same.
A classic Rubik's Cube consists of four main components:
- The core (x1)
- Center pieces (x6)
- Edge pieces (x12)
- Corner pieces (x8)
In a basic 3 x 3 x 3 cube, the core consists of a central assembly made of six poles protruding from each axis. This assembly remains stationary and immobile at all times. However, the poles act as axles that allow the center pieces to be rotated freely once they are attached. To hide this slotted attachment point, the colored tile for the center pieces are removable.
Whilst center pieces only contain one colored tile, edge pieces have two colored tiles, and corner pieces have three. Edge and corner pieces share a unique "fishtail" design that resembles the shell of a sphere when placed together. This design ensures overlap between all the pieces and allows room for them to rotate freely around the core, whilst preventing them from falling out of the assembled cube.
Once the six centers have been attached to the core, the edge and corner pieces are fit in the gaps between, solely held in place via neighboring pieces. This is the fundamental principle that allows a Rubik's Cube to be rotated in all directions. When only the center pieces have a fixed position, the edge and corner pieces can be moved freely relative to that position, and are prevented from falling out because they are essentially "sandwiched" between other pieces.