Eight classrooms, a new courtyard and 1,500 square metres of sheet metal that reflects its surroundings: Schwarzacher Becken primary school carries stainless steel cladding, mirror polished and coloured black. Instead of strong shades, hjp Architekten chose a surface that reads yellow when a postal van passes and blue when the sky allows. The concertina-folded metal facade cladding was installed with concealed fixings and adjusted to the millimetre at every window. Mirror polished stainless steel, coloured black electrochemically, without paint and without pigment.