How to solve a Rubik's cube without breaking your head

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How to solve a Rubik's cube without breaking your head
How to solve a Rubik's cube without breaking your head
Anonim

As you probably already know, a few days ago the world record for the fastest Rubik's cube was broken. Dutch speedcube Mats Valk at the 2016 Jawa Timur Open in Indonesia was able to collect the cube in an incredible 4.74 seconds. Do you know how to solve a Rubik's Cube? If not, then we have prepared for you detailed step-by-step instructions for assembling Erne Rubik's "magic cube".

How to solve the Rubik's Cube

What you need to know to solve the Rubik's cube

First, a few introductory installations to get an idea of ​​how to assemble a Rubik's cube:

1. There are several ways to solve the Rubik's cube. We chose one that seemed to us the most understandable and easy.

2. The assembly of the Rubik's cube takes place in several stages (steps). For example, in the first step, you collect the cross of the top face of the cube, and in the second, the corners of this face. Each stage has its own assembly algorithms (processes) written in formulas.

3. Your task at each stage will be to assess the situation, choose the appropriate algorithm and, having entered the starting position for its implementation, execute it. This will have to be done several times until the goal of the stage is achieved.

4. At each subsequent stage, the assembly algorithms are more complicated, and the formulas for writing them are longer. This is due to the fact that in addition to completing the main task of the stage (for example, to assemble a layer), you must also save what was done earlier - not to destroy the already assembled layers. in total, it will be impossible to collect it. In this case, it must be taken apart and folded again.

5. It is considered that no more than 20 rotations of the edges (moves) are enough to solve the cube. But usually many more moves are required.

6. In some cases, it is important not only the fact of solving the Rubik's cube, but also the time spent on the puzzle. High-speed assembly of the Rubik's cube is called speedcubing, and people who are fond of this activity are called speedcubers. Competitions for high-speed assembly of the Rubik's cube are held regularly. General structure of the Rubik's cube

Cube centers - 6 pcs. This item has only one sticker of the same color. The centers of the cube do not move relative to each other.

Cube edges - 12 pcs. The edge elements of the cube have two colors.

Cube corners - 8 pcs. The corner pieces have stickers in three colors.

Rubik's cube faces - these are nine of its elements that can be rotated at the same time.

Cube frame, on which the central elements of the faces are fixed. If you disassemble the cube mechanically, the cross and central elements will remain intact, and you can assemble the rest of the elements on them.

In total, there are 20 movable elements in the Rubik's cube (12 rib and 8 corner elements), since the central elements do not move relative to each other, we did not count them. Although, of course, they can move around the axis on the frame. Assembly sequence

1. Cross of the upper edge.

2. Top edge completely.

3. Middle layer.

4. Arrangement of the edge cubes of the last face in their places.

5. Orientation of side cubes - assembly of the cross of the last face.

6. Arrangement of corner cubes of the last face in their places.

7. Orientation of the corner cubes of the last face and, as a consequence, the assembly of the last face and the whole cube. Formulas

The assembly algorithms (processes), as we have already said, are written using formulas.The faces of the cube in the formulas are designated by letters according to the initial Russian letters of the names of the faces. Naturally, Latin designations are also used, but we will focus on the Russian ones.

F - facade

T - rear

П - right side

L - left side

B - top

H - bottom

You yourself determine which face of the cube at any given moment is considered a facade, that is, facing you. It depends on the current situation. You need to understand that the central cubes determine the color of the edge, which means that 6 cubes, even in the disassembled (confused) Rubik's cube, are already in their places. A 90 ° clockwise rotation is indicated as follows: F, T, P, L, V, N… In order to denote a 90 ° rotation counterclockwise, a stroke is applied: F ', T', P ', L', V ', N'.

C - this letter denotes a 90 ° clockwise rotation of the middle layer. С’- respectively, turn counterclockwise.

A standard process record might look like this: NPF 'P'. This formula is executed as follows:

1. Rotate the bottom edge 90 ° clockwise.

2. Rotate the right edge 90 ° clockwise, that is, away from you.

3. Rotate the front face 90 ° counterclockwise.

4. Rotate the right edge 90 ° counterclockwise, that is, towards yourself.

We will talk in more detail about recording processes at the build stages. In addition, you will need formulas if you are interested in other ways to solve the cube.

First step

Purpose: to collect the cross of the upper face - the first layer

In fact, the first two steps are the easiest. You practically do not need to fear the destruction of the previously collected layers, since you have practically not collected anything yet and you have a certain freedom of movement of the edges. You can use intuition or assembly algorithms.

At this stage, we are interested in the two-color edge elements of the cube. Choose the color of the edge you will collect first. From now on, it will be considered the top face, or the first layer. Now it is necessary to select edge elements for it. There are 12 edge elements in total, but we are only interested in four, one of the stickers of which has the color of interest to us - the color of the upper edge, that is, the upper central element.

Below is how the cube will look after the first stage. Please note: the cross descends to the side edges, as it were. If this does not happen, then it means that you have collected incorrectly.

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Suppose you selected the orange face for the assembly. Your task at this stage will be to find, in turn, all the edge elements with an orange sticker on the cube, and, having estimated their position, choose one of the algorithms in order to raise the element up. Both at this stage and on subsequent cubes can already stand in their places. This will make assembly easier, and in some cases, some steps can be skipped.

The starting position from which the algorithms of this stage are applied - the cube whose position you will change is located under the central cube of the front face. The corner cube is brought to its initial position by turning the bottom face, if it is on it, or first by the side (turning down), and then by the bottom, if it is located on one of the side faces.

Formulas for this stage:

F2 - the color of the edge element sticker facing you matches the color of the front edge

NPF'P ' - the color of the edge element sticker facing you matches the color of the top edge

A superscript two denotes two 90 ° turns (respectively, one 180 ° turn). F2= Ff… Turns are made to indicate counterclockwise or clockwise, there is no need, because in both cases the result is the same.

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Second phase

Objective: to collect the top face - the first layer

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At this stage, all algorithms are executed when the cube is in the lower left corner of the facade face you have chosen. In total, you need to find and place 4 corner cubes in the starting position. At the same time, each time you choose a new facade face.The cube in the corner can be turned in three ways in relation to the cube faces. Therefore, at this stage, three formulas are used.

Formulas for this stage:

LN'L 'situation "a"

F'N'Fsituation "b"

(F'P ') N2 (PF)situation "in"

Pay attention to the writing of the last formula. The parentheses are there to make it easier to remember. To learn how to solve a Rubik's cube, you need to memorize these formulas, but many processes are memorized intuitively.

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Stage three

Purpose: to collect the second layer (belt). As a result, two layers will already be collected.

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At this stage, you have two situations that determine which formula to apply and, accordingly, two formulas. You need to place 4 edge cubes in their places. In the starting position, the cube you are about to rearrange is under the center piece of the façade edge. To go to the starting position, find the desired cube on the bottom edge and bring it to the front, so that the colors of the central cube and the corner cube's stickers match, and the stickers are, respectively, next to each other. If the required cube is in the middle layer, then follow any of the algorithms of this stage until the cube drops to the bottom edge. It is recommended that you first arrange all the cubes that are below, and then proceed with those that are in the middle belt. Because as the lower ones are placed, the rib elements located in the middle belt can go down, and there will be no need to specially bring them to the lower layer.

Formulas for this stage:

(NLN'L ') (N'F'NF)if the element goes to the left side

(N'P'NP) (NFN'F ')if the element goes to the right side

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Fourth stage

The fourth and subsequent steps are designed to assemble the last face (last layer). The fourth and fifth are the assembly of the cross. The sixth and seventh are the correct placement of the remaining four corner pieces. From the fourth stage, the cube is turned upside down, so it will continue to be depicted in the illustrations.

The purpose of the stage: to arrange the edge cubes of the bottom face in their places. However, some of them will be incorrectly oriented.

At this stage, the pairs of edge cubes are swapped in one process. The process is performed several times until all the cubes fall into place. Again, two of them are likely to be mis-oriented.

The formula for this step:

(WFTU) B (P'V'F ')

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Fifth stage

Objective: orientation of the side cubes - assembling the cross of the last face

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By the fifth stage, as a rule, already two cubes of the last face should be in their places and at the same time correctly oriented. Rotate the top edge several times to verify this. Now you need to correctly orient the remaining edge cubes. The main sequence of this stage is changing the orientation of the cube on the right side, therefore, in most cases, three starting positions are possible for applying the algorithm. If all the cubes are incorrectly oriented, run the algorithm for the "c" situation twice.

Formulas for this stage:

(PSH)4 B (PSH)4 V'situation "a"

(PSH)4 B '(PSH)4 Vsituation "b"

(PSH)4 V2 (PSH)4 V2 situation "in"

All three formulas differ only in the way of turns, intermediate and final (B) and consist of one sequence - PSH… Record CH means rotating the middle layer clockwise. The subscript indicates which side to rotate from. That is, from which side of the face the rotation will be considered clockwise rotation. (WITHH)4 - means that this sequence should be performed four times.

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Sixth stage

Objective: to arrange the corner cubes of the bottom face in their places. However, some of them will be incorrectly oriented.

Both processes used in this step only affect the three corner cubes. One always stays in place.If, after the previous stage, you have a corner cube that is in its place, even if it is incorrectly oriented, then the choice of how you will hold the Rubik's cube in your hands and which face you choose as a front face depends on it.

It should be in the far left corner of the top edge. With the Rubik's cube oriented in this way, do one of two processes. They are mirrored, one is called direct, the other is reverse. The first moves the three corner cubes in a clockwise direction, the second in a counterclockwise direction. Choose the one that allows you to achieve your goal.

Formulas for this stage:

(P'F'L'F) (PF'LF)direct process

(F'L'FP ') (F'LFP)reverse process

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The algorithm is executed several times until all the cubes fall into place.

Seventh stage

Objective: the correct orientation of the corner cubes of the last face and, as a result, the assembly of the last face and the whole cube.

At this stage, it is easy to make mistakes and break everything that was collected earlier, so be careful when executing the formulas. As in the fifth step, the formulas consist of one sequence - PF'P'F… Moreover, in the algorithms, this sequence is repeated two times - (PF'P'F)2 - the so-called eight-way, or 8-way process. Here you need to understand that if the eight-move is repeated three times, then the whole cube will come to the same state as before starting the formula. To achieve the result, the algorithm is "diluted" with intermediate turns, that is, combined with V (turning the top edge 90 ° clockwise), V' (turning the top face 90 ° counterclockwise) and V2 (rotate the top edge 90 ° twice).

The formulas for this stage are as follows:

(PF'P'F)2 B (PF'P'F)2 situation "a"

(PF'P'F)2 B '(PF'P'F)2 situation "b"

(PF'P'F)2 V2 (PF'P'F)2 situation "in"

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In this case, the first half of the algorithm is performed until the corner cube is oriented correctly, and the second half (after turning) - until the lower layers, which have come into disarray during the first half, return to their previous assembled state. Now all that remains is to rotate the last assembled face and that's it - the Rubik's cube is complete!

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