A Sierpinski tetrahedron is formed by successive flakes of four regular tetrahedrons. Such shapes are called polyhedrons and include cubes as well as pyramids such as tetrahedrons. The minimum composition is two regular tetrahedrons along with an octahedron. In addition there can be borate BO triangles and BO tetrahedrons. A generalization of triangle centers to higher dimensions is centers of tetrahedrons or higher-dimensional simplices. It can be seen as the convex form with 4 tetrahedrons excavated around the sides. Instead of empty cells, every cell should be filled, with alternating inner tetrahedrons. The building's tetrahedrons form the walls and the pinnacled ceiling of the Protestant Chapel.