# Definition:Rubik's Cube

## Definition

**Rubik's cube** is a toy consisting of a plastic cube divided into $27$ smaller cubes, interlocking at the center cube and allowing each face to rotate independently of the others.

Each of the $6$ faces of the main cube is colored with one of six contrasting colors. Rotating the faces of the cube causes these $6$ faces to become mixed up.

The object of the exercise is to restore the $6$ faces to their original single colors.

## Parts of Rubik's Cube

### Faces

The **faces** of a Rubik's cube are simply the $6$ faces of the main cube which constitutes Rubik's cube.

### Subcubes

Each of the $26$ small visible cubes into which Rubik's cube is subdivided is called a **subcube**.

The $27$th cube is in the interior of Rubik's cube and therefore has no visible faces.

### Facets

Each of the $9$ small squares into which the faces of Rubik's cube is subdivided is called a **facet**.

## Types of Facet

### Corner Facets

Of each of the $9$ facets of each face of Rubik's cube, the $4$ in the corners of the face are called the **corner facets**.

The set of **corner facets** can be denoted $S_C$.

### Edge Facets

Of each of the $9$ facets of each face of Rubik's cube, the $4$ on the edges of the face are called the **edge facets**.

The set of **edge facets** can be denoted $S_E$.

### Center Facets

Of each of the $9$ facets of each face of Rubik's cube, the ones in the centers of the faces are called the **center facets**.

The set of **center facets** can be denoted $S_Z$.

## Basic Moves

The set of **basic moves** of the Rubik's cube can be denoted:

- $\set {U, D, L, R, F, B}$

where $U$, $D$, $L$, $R$, $F$, $B$ are in Singmaster notation.

## Also see

- Results about
**Rubik's cube**can be found**here**.

## Source of Name

This entry was named for Ernő Rubik.

## Sources

- 2008: David Joyner:
*Adventures in Group Theory*(2nd ed.) ... (previous) ... (next): Where to begin...