When you rotate a cube in three-dimensional space, its shadow on a flat surface looks like a square, changing and deforming as the cube turns. That shadow isn’t the cube itself, but a 2D projection of it. Now imagine doing the same with a 4-dimensional cube, also known as a tesseract. When it rotates in 4D space, what we would see in our 3D world is its shadow, a cube that appears to deform, stretch, and fold into itself. Just as the shadow of a cube hides one full dimension, the shadow of a tes

Exploring beyond 3D, the third dimension. Brian Greene talks about the possibility of dimensions of space. | Big Think