Arnaldo is an Italian sculptor born in 1926. He has works publically displayed all over the world and in many famous places. His work is usually is giant and made of cast bronze.
The unpolished parts of the bronze he cast is a perfect surface for the sunk in cave like parts of his sculptures. Then there are parts of his sculptures that he buffs to a shine and that have a mirror effect. The contrast of these two surfaces creates the illusion of his large spherical pieces and rectangular pieces to have extreme depth or that the whole thing is solid bronze.
Many of his pieces are made by creating large blocks made of sand and glue. Then he carves into these large blocks and carves all around on the surface. After this step he makes a large mold of this piece and reproduces that casting out of wax. After he has the wax form he then coats that in a ceramic slip and fires that in a kiln. The wax melts out of the kiln and is recycled. After the wax melts out of the mold it is then heated up to a very high temperature and the bronze is then poured into that hollow form and once it cools off the shell or mold is then knocked off by breaking it into small pieces.On pieces like the one that was shown at the Vatican he makes it appear that there is one form inside the other. This is a talent that not many have in the sculpture world.