Cube
The 2-dimensional (2D) shape (like a circle, square, triangle, etc.) that a cube is made of is squares. The sides (faces) of a cube are squares. The edges are straight lines. The corners (vertices) are at right angles.  A cube has 8 corners, 12 edges and 6 faces, as in the most usual kind of dice. A tesseract carries this idea into the fourth dimension (4D) and is made of 8 cubes.