The mosaic 'Die vier Elemente' by Hans Stocker transforms a school corridor into a vibrant lesson in ecology and imagination. Created posthumously in 1984 from the artist's designs, its bright glass depicts a gardener tending to plants, surrounded by the radiating colors of water, earth, air, and fire. The circular composition is deliberately broken open, inviting students and passersby into its world. Here, the sun is not just a symbol of an element but becomes a focal point for play and daydreams, proving that public art in a functional space can quietly nurture both environmental awareness and creative wonder.