# Rubik's Cube: A Dream From My Childhood

The original Rubik's Cube is a 3x3 cube. If you already know how to solve a classic 3x3 Rubik's Cube, then you will also know how to solve a 2x2 if you realize that:

A 2x2 cube is a 3x3 cube with only corners!

## STEP1: SOLVE THE WHITE LAYER

Our first step is to create the white layer on the Rubik's Cube, ensuring that the colors on the sides are also correct. For example, in Fig 1.1, although there's a white layer, it's not correctly solved. In contrast, Fig 1.2 shows a white layer that is correctly solved. This step doesn't require a specific formula; instead, practice is essential.

Now, let's rotate the cube 180 degrees to position the white layer at the bottom.(Fig 1.3)

## STEP2: MAKE THE UPPER LAYER ALL YELLOW

### (a) There are 3 non-yellow color on the upper layer (Fig. 4a and Fig. 4b)

In this case, the upper layer has one yellow color, while the other three colors are incorrect. Let's first turn the cube left or right until the yellow color is in a back-right or back-left position, ensuring there is a yellow color on the back-layer.

If the yellow color on the upper layer is in the back-left corner (Fig.2a) using formula

R' U' R U' R' U'2 R

If the yellow color on the upper layer is in the back-right corner (Fig.2b) using formula

L U L' U L U2 L'

Note that the two formulas are mirror images of each other.

Fig.2a
Fig.2b
Fig.2c
Fig.2d

### (b)There are two cubies whose colors are incorrect (Fig.2c)

In this case, we first turn the cube so that the color at the back of the left-back corner cubie is yellow, then apply formula R' U' R U' R' U'2 R, the cube will show one of the configuration in (a).

### (c) There are four cubies whose colors are incorrect (Fig.2d)

In this case, we first turn the cube so that the color at the left of the left-back corner cubie is yellow, then apply formula R' U' R U' R' U'2 R, the cube will show one of the configuration in (a).

## STEP3: REARRANGE THE UPPER LAYER'S CORNER PEICES

### One side has matching colors (refer to Fig.3a)

In this case, place the side with matching colors on the right side and make the yellow layer the front layer (facing us). Apply the formula

R2 D2 R' U' R D2 R' U R'

### No matching colors on any side (refer to Fig.3b)

In this situation, it doesn't matter which side is on the right, but ensure the yellow layer is the front layer. Apply the previous formula, then the cube will have a matching colors on the side, back to the previous situation.

### Formula Practice

That's it. You have solve the 2x2 Rubik's cube. Have fun!