'Nude desending a staircase, nr.2' by Marcel Duchamp - 1912

Gertrude Stein, the cubist writer as she called herself, describes the situation of painting at the time as follows: “After Cézanne, everyone who painted wanted to create the sensation of movement within the picture, not by painting something that moved but rather by depicting the existence of movement in the object itself”.

In Duchamp's picture you have both: the sensation of the movement in the time sequence and the very existence of the movement in the subject 'nude'.
Before it was common to freeze a nude, lying or standing, in the picture. To descend a nude was new! Duchamp confirmed it by writing the title in the lower left corner.
A painting, he said, 'is the diagram of an idea'.

‘Nu descendant un escalier, n°2’ - 147 cm × 89 cm (58” × 35”)

Collection Philadelphia Museum Of Art