Liubov Popova (1889-1924), "Composition 21 / Painterly-Force Construction", 1921. Oil on canvas. Russian avant-garde abstract composition executed in a dynamic Cubo-Futurist/Constructivist vocabulary of intersecting geometric planes, bold black linear elements, fragmented forms and numerals. Inscribed "Composition 21" at lower left and signed at lower center. The reverse of the original canvas bears a faint but legible Cyrillic inscription ("Painterly-Force Construction") and is clearly dated "1921", together with additional partially effaced inscriptions. Canvas: 16 x 20 in. (40.6 x 50.8 cm). Framed: 24.5 x 28.5 in. (62.2 x 72.4 cm).