Tesseract

four-dimensional analogue of the cube

A tesseract is a 4-dimensional object with eight cells; each cell is a cube. Unlike three-dimensional objects which rotate on both an axis and a plane (the plane being of length and width and the axis being of the leftover dimension, height), a tesseract rotates on two planes, one made up of length and width, and one made up of height and the fourth dimension. It is the simplest hypercube.

3D projection of a tesseract, rotating along one axis

It is not possible to make a tesseract out of real materials. A tesseract is in four dimensions, but we can only move in three dimensions.

A Line is to the 1st dimension, Square is to the 2nd dimension, Cube is to the 3rd dimension, Tesseract is to the 4th dimension.