Stupid was a short-lived grouping of constructivist artists, formed in Cologne in 1919.  The founding members were Willy Fick, Heinrich Hoerle, Angelika Hoerle, Anton Räderscheidt, Marta Hegemann, and Franz Wilhelm Seiwert. 
The Stupid group aimed to address sociopolitical issues through an art of proletarian character.  Seiwert and Räderscheidt had previously been active in the Cologne Dada scene, along with Max Ernst. Ernst later described Stupid as "a secession from Cologne Dada. As far as Hoerle and especially Seiwert were concerned, Dada's activities were aesthetically too radical and socially not concrete enough".  Seiwert described the group's esthetic: "We are attempting to be so clear that everyone will be able to understand us." 
Räderscheidt's studio was their base of operations, but by 1920 he had abandoned the constructivist style.  The group exhibited together and issued a publication, "Stupid 1", before disbanding. Many of the members joined the Cologne Progressives group. 
Dada or Dadaism was an art movement of the European avant-garde in the early 20th century, with early centres in Zürich, Switzerland, at the Cabaret Voltaire. New York Dada began c. 1915, and after 1920 Dada flourished in Paris. Dadaist activities lasted until c. the mid 1920s.
Max Ernst was a German painter, sculptor, graphic artist, and poet. A prolific artist, Ernst was a primary pioneer of the Dada movement and surrealism. He had no formal artistic training, but his experimental attitude toward the making of art resulted in his invention of frottage—a technique that uses pencil rubbings of objects as a source of images—and grattage, an analogous technique in which paint is scraped across canvas to reveal the imprints of the objects placed beneath. He is also noted for his novels consisting of collages.
Modern art includes artistic work produced during the period extending roughly from the 1860s to the 1970s, and denotes the styles and philosophies of the art produced during that era. The term is usually associated with art in which the traditions of the past have been thrown aside in a spirit of experimentation. Modern artists experimented with new ways of seeing and with fresh ideas about the nature of materials and functions of art. A tendency away from the narrative, which was characteristic for the traditional arts, toward abstraction is characteristic of much modern art. More recent artistic production is often called contemporary art or postmodern art.
Degenerate art was a term adopted in the 1920s by the Nazi Party in Germany to describe modern art. During the dictatorship of Adolf Hitler, German modernist art, including many works of internationally renowned artists, was removed from state-owned museums and banned in Nazi Germany on the grounds that such art was an "insult to German feeling", un-German, Jewish, or Communist in nature. Those identified as degenerate artists were subjected to sanctions that included being dismissed from teaching positions, being forbidden to exhibit or to sell their art, and in some cases being forbidden to produce art.
Loplop, or more formally, Loplop, Father Superior of the Birds, is the name of a birdlike character that was an alter ego of the Dada-Surrealist artist Max Ernst. Ernst had a ongoing fascination with birds, which often appear in his work. Loplop functioned as a familiar animal. William Rubin wrote of Ernst "Among his more successful works of the thirties are a series begun in 1930 around the theme of his alter ego, Loplop, Superior of the Birds." Loplop is an iconic image of surrealist art, the painting Loplop Introduces Loplop (1930) appears on the front cover of the Gaëtan Picon's book Surrealist and Surrealism 1919-1939, and the drawing and collage Loplop Presents (1932) was used as the frontispiece of Patrick Waldberg's book Surrealism.
The New Objectivity was a movement in German art that arose during the 1920s as a reaction against expressionism. The term was coined by Gustav Friedrich Hartlaub, the director of the Kunsthalle in Mannheim, who used it as the title of an art exhibition staged in 1925 to showcase artists who were working in a post-expressionist spirit. As these artists—who included Max Beckmann, Otto Dix, George Grosz, Christian Schad, Rudolf Schlichter and Jeanne Mammen—rejected the self-involvement and romantic longings of the expressionists, Weimar intellectuals in general made a call to arms for public collaboration, engagement, and rejection of romantic idealism.
Sophie Henriette Gertrud Taeuber-Arp was a Swiss artist, painter, sculptor, textile designer, furniture and interior designer, architect, and dancer.
Constructivism was an artistic and architectural philosophy that originated in Russia beginning in 1915 by Vladimir Tatlin and Alexander Rodchenko. Abstract and austere, constructivist art aimed to reflect modern industrial society and urban space. The movement rejected decorative stylization in favor of the industrial assemblage of materials. Constructivists were in favour of art for propaganda and social purposes, and were associated with Soviet socialism, the Bolsheviks and the Russian avant-garde.
Anton Räderscheidt was a German painter who was a leading figure of the New Objectivity.
German art has a long and distinguished tradition in the visual arts, from the earliest known work of figurative art to its current output of contemporary art.
Franz Wilhelm Seiwert was a German painter and sculptor in a constructivist style. He was also politically active as a communist making significant contributions, both graphic and theoretical to Die Aktion.
Heinrich Hoerle was a German constructivist artist of the New Objectivity movement.
Marta Hegemann was a German artist associated with the Dada movement and with the Cologne Progressives. She was a founding member of the Cologne art group Stupid.
Werner Spies is a German art historian, journalist and organizer of exhibitions. From 1997 to 2000, he was also a director of the Centre Georges Pompidou in Paris. According to Klaus Albrecht Schröder, director of the Albertina, Vienna, Spies is "one of the most influential art historians of the 20th century."
Georg Muche was a German painter, printmaker, architect, author, and teacher.
Wilhelm Peter Hubert Fick, called Willy Fick, was a German graphic artist born in Cologne. He belonged to the Dada movement, and in 1919 became a founding member of the artist circle called Stupid, together with Heinrich Hoerle, Angelika Hoerle (1899–1923), who was the sister of Willy Fick and the wife of Heinrich Hoerle, Anton Räderscheidt, his wife Marta Hegemann, and Franz Wilhelm Seiwert. Fick was a Cologne dadaist from 1916 until 1923 and a scholarship student of Jan Thorn-Prikker at the Cologne School of Applied Arts /Kölner Werkschulen from 1928 until 1931. Duesseldorf art agent Johanna Ey represented his Weimar period works. Many works were destroyed by bombing in World War II but preserved in archival photographs in the Rheinisches Bildarchiv / Rhineland Picture Archive. Fick painted and cartooned until his death in Canada in 1967.
The Cologne Progressives was an art movement and were an informal group of artists based in the Cologne and Düsseldorf area of Germany. They came together following the First World War and participated in the radical workers' movement.
Angelika Hoerle was a German Dada artist who was a founding member of the Cologne art group Stupid and the cofounder of a Dadaist publishing house.
Figurative Constructivism is an art movement that arose principally in Germany. The term was introduced by Franz Seiwert in 1929 using the phrase "gegenständlichen constructive", and this was subsequently taken up by Gerd Arntz and then by art historians more generally. It is closely related to the development of the Isotype. As Seiwert wrote "From the expressionist-cubist art-form abstract constructivism was developed, which in turn led into Figurative Constructivism".
Augustin Tschinkel was a Czech artist active with the Figurative Constructivist art movement.