To build the exterior FishWitch set - the iceberg visible above water and the outside of the protagonist's home - I helped the production designer, Lizzie Osborne, to carve the mushroom cloud shape and its platform from polystyrene using a hot wire tool, before coating it in layers of fibreglass and an epoxy resin to create a solid shell. The gruelling part came next - cutting, melting and clawing out the polystyrene with our hands so that the translucent shape could be coloured from the inside. Once the ice forms had been painted, we created patterns of snow with a Toupret and marble dust mixture, planting spare resin pieces in the snow and sculpting delicate icicles to hang from the platform. 

To provide some background texture, I carved some smaller icebergs from polystyrene and spray painted shadows to emphasise their grooves - I also added shading to the snowy platform with an airbrush for a similar effect.