In the book > Farber, Michael. *Invitation to topological robotics*. European Mathematical Society, 2008, Farber uses C&P (cut & paste) surgery and the Grothendiek ring $\mathfrak{C}$&$\mathfrak{P}$ to compute Euler characteristics of polyhedral configuration spaces (pp.55-56): <hr /> ![C&P][1] <hr /> (This is not a topic with which I am intimately familiar, but I offer it as a connection between robotics and Grothendiek's work.) [1]: https://i.sstatic.net/h0r6f.png