Rotation in four-dimensional space
The 5-cell is an analog of the tetrahedron.
Tesseract is a four-dimensional hypercube - an analog of a cube.
The 16-cell is an analog of the octahedron.
The 24-cell is one of the regular polytope.
A hypersphere is a hypersurface in an n-dimensional Euclidean space formed by points equidistant from a given point, called the center of the sphere.