A hypercube (also known as a tesseract) is to a cube as a cube is to a square. Just as a cube is a three-dimensional extension of a square in two dimensions, a hypercube is a four-dimensional extension of a cube in three dimensions. It’s a mathematical concept that represents a higher-dimensional analog of a cube. While it’s challenging to visualize a hypercube directly, the analogy demonstrates the pattern of extending shapes to higher dimensions.