4x4

4x4, read as four by four, denotes a two-dimensional arrangement with four units along each of two axes. It is used in mathematics, geometry, and design to describe grids, matrices, and layouts that consist of 16 elements in total.

In mathematics and computing, a 4x4 matrix is a square array with four rows and four columns, containing sixteen entries. Such matrices are used to represent linear transformations, coordinate data, or system of equations, and they support operations like addition, multiplication, and determinants. The term also appears in reference to 4x4 grids or blocks in various applications, including image tiling and grid-based representations.

In games and puzzles, 4x4 appears in the 4x4 sliding puzzle (also known as the 15 puzzle), which features fifteen movable tiles and one empty space arranged on a 4x4 grid. 4x4 Sudoku refers to Sudoku puzzles that are solved on a 4 by 4 grid, a smaller variant of the standard 9x9 version.

In transportation, 4x4 describes four-wheel-drive systems where power is delivered to all four wheels. This term is commonly used for off-road and utility vehicles, indicating a drivetrain configuration with two axles that can be connected to power simultaneously. Vehicles labeled as 4x4 may have part-time or full-time four-wheel drive and sometimes include a low-range mode for difficult terrain.

The concept also appears in other contexts, such as 4x4 layouts in digital displays, tiling, or spatial design, where a square footprint of four by four units is employed for organization or patterning.