Kazimir Malevich exhibited his first "Black Square" in 1915. Marking the beginning of non-objective art, it is considered an icon of 20th-century painting. The 79.5 x 79.5 cm square oil painting is now hanging in the Tretyakov Gallery in Moscow. In 1923, Malevich painted yet another "Black Square."

Malevich (1879-1935) started out with Russian folk painting. Later on, he developed the ideas for "Suprematism," a radically abstract art movement related to futurism. Paintings were liberated from any reference to objects and reduced to simple geometric shapes. In this way, Malevich wanted to express the "highest principles of human knowledge." Here is an untitled painting from 1915.

Another artist inspired by squares was Kurt Schwitters (1887-1948). Shown here is his painting "Quadrat B" (1922-1925). The German artist, painter, poet and printmaker developed a one-man movement called "Merz." His works are associated with Constructivism, Surrealism and Dadaism. Schwitters is one of the most influential artists of the early 20th century.

The famous American painter Mark Rothko (1903-1970) also worked with squares. After producing some realistic paintings, he then embarked on a surrealist phase. He became known as an Abstract Expressionist who intensively studied the significance of light and color. This picture shows two paintings by Rothko in the Kunsthalle Hamburg in 2008.

The German painter and art teacher Josef Albers (1888-1976) devoted himself to the systematic exploration of color and form in painting - including in his great series "Homage to the Square." Shown here is his painting "Pronounced" (1961). Albers experimented with the spatial perception of color, greatly influencing abstract painting after the Second World War.

The Swiss architect, artist and designer Max Bill (1908-1994) was a member of the Zurich School of Concrete Artists. For him, concrete art was the expression of harmonious form, a way of organizing systems which acquire life through artistic means. Shown here is his oil painting "Farbfeld mit weißen und schwarzen Akzenten" (Color field with white and black accents,1964-1966)

The Swiss painter Verena Loewensberg also belonged to the Zurich School of Concrete Artists. She chose to work without titles and comments and was against a formulated theory of her art. This work of hers created in 1966 can be seen at the exhibition "A Square is a Square is a Square..." shown in the Museum Ritter in Waldenbuch in Baden-Württemberg from May 10 to September 20, 2015.

In his neon object "Récréation No. 6" (1994), the French artist François Morellet combined the perfect shape of the square with the imperfection of real things. He fastened three slightly bent neon tubes horizontally and vertically on a square plate, creating a grid of sixteen surfaces. The lit tubes add a new dimension to the piece.

Vera Molnár, a French artist born in Budapest in 1924, is considered a pioneer of digital art. She uses computer programs to generate random patterns of shapes, colors and geometry in her serial work. Through sequences of similarly sized forms - such as squares - she creates linearity and movement. This picture shows her work "Pink et Rouge" (1996).

The German artist and professor emeritus Timm Ulrichs sees himself as a "total artist." In 1961, he declared himself "the first living work of art." Ulrichs not only exhibits himself, he also works with the geometric precision of the square. His installation "The Favorite Colors of the Lower Saxons" (2009) is a 90-meter (295 ft) long wall covered with colorful square plates.

Kazimir Malevich exhibited his first "Black Square" in 1915. Marking the beginning of non-objective art, it is considered an icon of 20th-century painting. The 79.5 x 79.5 cm square oil painting is now hanging in the Tretyakov Gallery in Moscow. In 1923, Malevich painted yet another "Black Square."

Malevich (1879-1935) started out with Russian folk painting. Later on, he developed the ideas for "Suprematism," a radically abstract art movement related to futurism. Paintings were liberated from any reference to objects and reduced to simple geometric shapes. In this way, Malevich wanted to express the "highest principles of human knowledge." Here is an untitled painting from 1915.

Another artist inspired by squares was Kurt Schwitters (1887-1948). Shown here is his painting "Quadrat B" (1922-1925). The German artist, painter, poet and printmaker developed a one-man movement called "Merz." His works are associated with Constructivism, Surrealism and Dadaism. Schwitters is one of the most influential artists of the early 20th century.

The famous American painter Mark Rothko (1903-1970) also worked with squares. After producing some realistic paintings, he then embarked on a surrealist phase. He became known as an Abstract Expressionist who intensively studied the significance of light and color. This picture shows two paintings by Rothko in the Kunsthalle Hamburg in 2008.

The German painter and art teacher Josef Albers (1888-1976) devoted himself to the systematic exploration of color and form in painting - including in his great series "Homage to the Square." Shown here is his painting "Pronounced" (1961). Albers experimented with the spatial perception of color, greatly influencing abstract painting after the Second World War.

The Swiss architect, artist and designer Max Bill (1908-1994) was a member of the Zurich School of Concrete Artists. For him, concrete art was the expression of harmonious form, a way of organizing systems which acquire life through artistic means. Shown here is his oil painting "Farbfeld mit weißen und schwarzen Akzenten" (Color field with white and black accents,1964-1966)

The Swiss painter Verena Loewensberg also belonged to the Zurich School of Concrete Artists. She chose to work without titles and comments and was against a formulated theory of her art. This work of hers created in 1966 can be seen at the exhibition "A Square is a Square is a Square..." shown in the Museum Ritter in Waldenbuch in Baden-Württemberg from May 10 to September 20, 2015.

In his neon object "Récréation No. 6" (1994), the French artist François Morellet combined the perfect shape of the square with the imperfection of real things. He fastened three slightly bent neon tubes horizontally and vertically on a square plate, creating a grid of sixteen surfaces. The lit tubes add a new dimension to the piece.

Vera Molnár, a French artist born in Budapest in 1924, is considered a pioneer of digital art. She uses computer programs to generate random patterns of shapes, colors and geometry in her serial work. Through sequences of similarly sized forms - such as squares - she creates linearity and movement. This picture shows her work "Pink et Rouge" (1996).

The German artist and professor emeritus Timm Ulrichs sees himself as a "total artist." In 1961, he declared himself "the first living work of art." Ulrichs not only exhibits himself, he also works with the geometric precision of the square. His installation "The Favorite Colors of the Lower Saxons" (2009) is a 90-meter (295 ft) long wall covered with colorful square plates.