A “Mapper” is a component that takes a Karamba3D-model and modifies it according to some generic rules defined by mappings, based on parameters supplied by the user. It acts directly on the model, so the process of transferring Grasshopper-geometry to a Karamba3D-model is dispensed with. The resulting gain of speed can be important when running optimization tasks with e.g. Galapagos. Fig. 188.8.131.52 shows a definition where a mapper applies a mapping called “Simple Stitch” on a given model which originally consists of two elements: “A” and “B”. In this case there is one mapping that connects two beam-sets with elements whose position is controlled by the parameters given to the mapper. In other words: a mapping is a functor.