 These four innermost house columns support a roof that is the steepest of all type of Javanese roof; almost forming a pyramid, except that it comes to two points rather than a single one.These four innermost main house columns is surmounted by a unique structural element known as "tumpang sari".A "tumpang sari" is basically layered beams structure; the outermost band of beams support the rafters of both the upper and lower roofs, while the heavily-ornate inner band of beams create a vaulted ceiling in the form of an inverted stepped pyramid.