Marcel Duchamp brief.

Marcel Duchamp (Heri-Robert-Marcel Duchamp) is an American artist mostly recognized in painting and sculpting. He was famous as a chess-player beside as a great figure of experimental art as well. He was considered as one of the three artist who helped define and promoted the development of plastic art and in 20th century along with Pablo Picasso and Henri Matisse. As a prominent figure in art history, he redefined the art in some way by introducing conceptual art to the world, where the term "Ready made" comes from.
A ready made is a piece of art but almost completely based on a found object; Duchamp took the found object and simply sign it or reposition it to turn the ordinary object to a piece of modern art.

Fountain by Marcel Duchamp

Bicycle wheels by Duchamp