IPC codes underlying your layers in Figure 1 "Other Circular Patents" classification
SOURCE: Portillo-Tarragona, P.; Scarpellini, S.; Marín-Vinuesa, L.M. (2022 online).‘Circular patents’ and dynamic capabilities: new insights for patenting in a circular economy. Technology Analysis & Strategic Management. DOI: 10.1080/09537325.2022.2106206