Manufactured objects promoted to the dignity of art through the choice of the artist. Duchamp invented the readymade, and said that his selection of objects was guided completely through indifference. He showed that art could be made out of anything, through little to no manipulation by the artist. Rectified readymades are made by altering or marking established works of art. For example, Duchamp added a mustache and beard to the Mona Lisa, titling it LHOOQ. Rectified readymades mocked and challenged traditional art. Assisted readymades required some artists intervention, such as mounting a bike wheel on a kitchen stool.