Final answer:
Malevich's most famous painting is Black Square, which became the signature image of the Suprematism movement. Suprematism is a Russian abstract movement characterized by flat geometric shapes on plain backgrounds.
Step-by-step explanation:
Malevich's most famous painting is Black Square. This painting became the signature image of the Suprematism movement that Malevich called for. Suprematism is a Russian abstract movement that originated in 1913 and is characterized by flat geometric shapes on plain backgrounds, emphasizing spiritual qualities of pure form.