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Influential artist and theorist Jean Metzinger played a pivotal role in the development of Cubism. He was a founding member of the Puteaux Group, a collective of artists who experimented with the fragmentation and reassembly of forms. Metzinger's theoretical writings, such as "Note on Painting" (1910), helped to define the Cubist movement and its emphasis on multiple perspectives and the interplay of positive and negative space.