Langton's Ant is a two-dimensional Turing machine invented by Chris Langton in 1986. It consists of a simple set of rules governing the movement of an "ant" on a grid of black and white cells. The ant changes the color of the cell it visits and turns either left or right based on the color of the cell. Initially, the ant's movement appears chaotic, but after a series of steps, it eventually creates a repeating pattern known as a "highway." This phenomenon demonstrates how simple rules can lead to complex behavior, making Langton's Ant a popular example in the study of emergent systems and cellular automata.