Apollo is an aluminium casted stool.
Liquid aluminium is poured in a circular sand imprint. After it reaches the top, extra aluminium is slowly added to form a drop shape. Instead of overflowing, the surface tension hold the metal and creates a natural radius around the plate.
As the mould is open the top cools faster that the heart of the piece. This generates random reliefs over the surface, making each stool a one-off piece.