How can a 5 year old solve a Rubik's cube even before learning how to properly write their name? It's amazing to see kids solving Rubik's cubes and sometimes in the rapid category, below the 1 minute mark. But still, how do they do it? and most important, can you do it too?

The history behind Rubik's Cube

The Rubik's cube was invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik. It is now the most sold puzzle in the world, with manny different versions: 3x3x3, 4x4x4, 25x25x25, and some of them aren't even cubes: cylinders, pyramids and many other shapes.

Hands solving the Megamix. Photo by ALAN DE LA CRUZ on Unsplash

What is most fascinating about the Rubik's cube is that it is really difficult to solve if you don't know how to do it prior, but really easy if you know the steps to take. You may try to solve it randomly or with your intuition, but there are 88,580,102,706,155,225,088,000~~(I don't even know how to spell this number)~~ possible permutations of the cube, it may take a life time to solve it this way.

They've cracked the code

It took a month for Ernő to solve the puzzle in the first time. But since them, people have solved it thousands of times and with the astonishing 3.47 seconds world record. Researchers, mathematicians, programmers and many others came up with a way to solving the cube, which involve taking some meticulous steps. For example, at first you should choose one color to be a base for the cube, and solve it. Afterwards you start building your way to the top. Solve the second layer, and finally the last layer.

Okay, but you still haven't told us how to do it, Thiago! That's a good point. I'm not the better person to tell you how to do it, there's plenty of good rubik's cube solving techniques online. But my investigation relies on why everyone can solve it. And it is because it is simply following some steps that the others have already tolds us how to.

Solving the Rubik's cube is a matter of following some rigorous steps. Their structure is the same everytime, but what it changes is the adaptation for everyone of the different permutations.

There are beginners and advanced methods, which ones will take their own time to learn. Learning the advanced methods will help you solve it faster, but will need more muscle memory and lots of training.

Rigorous steps

For that, they created a notation that people can follow. For example, if I told you, do this LU′ R′ U L′ U′ R U2 with your cube, probably you wouldn't know what it means, but it is actually a way of saing which pieces of the cube to move and in which direction. Some of the patterns:

• F (Front): the side currently facing the solver
• B (Back): the side opposite the front
• U (Up): the side above or on top of the front side
• D (Down): the side opposite the top, underneath the Cube
• L (Left): the side directly to the left of the front

The a prime symbol ( ′ ) after a letter denotes an anticlockwise face turn; and a letter followed by a 2 denotes two turns.

In the end, you could memorize each step with a conjunction of Fs and Bs and Us, but you could also memorize them visualy. If you follow one of the tutorials you see that it actually makes sense and works, you just need to repeat that.

This repetition of movements and actions defined by how your cube is in that moment can also be called an algorithm.

Algorithms, again?

Yep! Programmers love Rubik's cubes because they follow a pattern, an algorithm. If I have a red middle piece right next to a blue one, I can do a F B F2 L and have it in the right place. Even if I just memorized that pattern in a written, visual or singing-a-song way, it works everytime. If, in the end, it doesn't work, it means that I did something wrong along the way.

It is also a challenge to solve the Rubik's cube faster and faster. It's an amazing thing to see how computers solve the cube. Some researchers created an algorithm that optimizes the way to solve the cube. It's basically an algorithm that tries to be better than other algorithms. It's really meta.

Now, what?

Computers, children, and anyone else can solve the cube, you just need to give them an algorithm. A path to follow. Rubik's cubes having been around for a while and they still are a challenge, but they don't need to be.

I endorse you to learn how to solve the cube, and understand what an algorithm is about. If you don't want to follow some pattern or rigorous steps, feel free to click on the serendipity roulette and be surprised by an expected permutation in the world of articles.