"Rotation in four-dimensional space.https://youtu.be/vN9T8CHrGo8The 5-cell is an analog of the tetrahedron.https://youtu.be/z_KnvGGwpAoTesseract is a four-dimensional hypercube - an analog of a cube.https://youtu.be/HsecXtfd_xsThe 16-cell is an analog of the octahedron.https://youtu.be/1-oj34hmO1QThe 24-cell is one of the regular polytope.https://youtu.be/w3-TqPXKlVkThe hypersphere is an analog of the sphere."