Rhythm is the visual tempo set by repeating elements in a work of art or architecture. The arches and columns of San Lorenzo in Florence, from the fifteenth century, set a good example. They are spaced very evenly, setting up an even, calm tone to the building. The octagons on the ceiling contribute to this effect, with their consistent rhythm. All of this helps us to move steadily and calmly forward through the space, to the altar of the church at the far end.
For contrast, we could look at Jackson Pollock’s Autumn Rhythm (#30), 1950. Pollock was a fan of jazz music, and tried to capture something of its loose, syncopated rhythms. The resulting drip-paintings (they were made with the large canvases lain on the floor of his studio) have similarly loose, free compositions, but there is a clear rhythm running horizontally across the work.