Do you know how to distinguish cube edges, corners and walls? All sides of a square are equal. All angles of a square are equal (right). The diagonals are smooth and perpendicular. The diagonals divide the corners of the square in half. The intersection of a square diagonal divides each diagonal in half. If this description has not given you positive emotions and you do not want to read again - watch the cube. The fusion of video and audio will provide this knowledge in and of itself.