The cupola is distinguished for its trefoil arch .
The octahedron turns to a hexahedron with the help of trumpet arches and then turns into a circle of the cupola with the help of angular rosettes .
The cupola is distinguished for cupola 's trefoil arch .
The octahedron turns to a hexahedron with the help of trumpet arches and then turns into a circle of the cupola with the help of angular rosettes .