This country was the home of the author of Concerning the Spiritual in Art, the cofounder of the Blue Rider group.
Two brothers from this country, Gabo and Pevsner, wrote the "Realistic Manifesto." One artist from this country created a series of geometric paintings called "Prouns," in addition to a work in which a red wedge stabs a white circle. One artist from this country founded the Suprematism movement, which led to such works as Black Square and White on White. This country was the home of the author of Concerning the Spiritual in Art, the cofounder of the Blue Rider group. For 10 points, name this country, home to Kasimir Malevich and Wassily Kandinsky.
Two brothers from this country, Gabo and Pevsner, wrote the "Realistic Manifesto.
Russian Federation [or Soviet Union; or USSR]