Bruno Taut, Glass Pavilion for 1914 Werkbund exhibition in Cologne:

Bruno Taut’s structure demonstrated the various ways glass could be used in a building, but also indicated how the material might be used to orchestrate human emotions and assist in the construction of a spiritual utopia… The glazed walls were topped by a dome of reinforced concrete ribs and a double skin of glass: reflecting glass on the outside and coloured prisms inside. In the interior, the colour effects produced by sunlight were enhanced by the reflections of the pool and water cascade on the lower level, visible through a circular opening in the floor. Two flights of glass steps enclosed with glass walls produced the sensation of descending to the lower level ‘as if through sparkling water’. The cascade was made of yellow glass, while the pool was of its complementary colour, violet. A mechanical kaleidoscope overhead projected images, an early version of a light show, intensifying the overall impression on the visitor.