During the summer semester of 2025 i had a professorship at the HfG Karlsruhe in the graphic and product design department. My seminar on hammers and sandcastles explored the relationship between human animals and tools. How do we use tools? How do tools use us?. Starting from the so-called law of the instrument and along some of the writings on Tools for Conviviality (excerpt), the students were working on own hammer handles, on no-input sound, nailed furniture, and conducting research on tools for the school. All works shown here are made by the students.