Complex sentence: In 1921, Rodchenko executed what were arguably some of the first true monochromes (artworks of one color), and proclaimed I reduced painting to its logical conclusion and exhibited three canvases: red, blue, and yellow.
Split into simpler sentences: In 1921, Rodchenko executed what were arguably some of the first true monochromes (artworks of one color). Rodchenko later proclaimed, I reduced painting to its logical conclusion and exhibited three canvases: red, blue, and yellow.