Source: https://www.researchgate.net/profile/Hassan-Squalli/publication/331053762_Developper_la_pensee_algebrique_a_travers_une_activite_de_generalisation_basee_sur_des_motifs_patterns_figuratifs/links/5d8a2d1e299bf1996fa42e43/Developper-la-pensee-algebrique-a-travers-une-activite-de-generalisation-basee-sur-des-motifs-patterns-figuratifs.pdf