Cube only member of that group that is a zonohedron (every face has point symmetry). The cube can be cut into six identical square pyramids. If these square pyramids are then attached to the faces of a second cube, a rhombic dodecahedron is obtained (with pairs of coplanar triangles combined into rhombic faces). The analogue of a cube in four-dimensional Euclidean space has a special name—a tesseract or hypercube. More properly, a hypercube (or "n"-dimensional cube or simply "n"-cube) is the analogue of the cube in "n"-dimensional Euclidean space and a tesseract is the order-4 hypercube. A hypercube is also called
Cube root of a number "x" are the numbers "y" which satisfy the equation For any real number "x", there is "one" real number "y" such that "y" = "x". The cube function is increasing, so does not give the same result for two different inputs, plus it covers all real numbers. In other words, it is a bijection, or one-to-one. Then we can define an inverse function that is also one-to-one. For real numbers, we can define a unique cube root of all real numbers. If this definition is used, the cube root of a negative number is a negative number.