According to the Merriam-Webster Online Dictionary, rhythm is “movement, fluctuation, or variation marked by the regular recurrence or natural flow of related elements”.
Artists can either choose to create a hyper-energized or dynamic artwork, something more calming and fluid, or something more orderly and geometrically structured.
A flowing rhythm is when a pattern follows the “organic” patterns made by nature, which are typically circular or curved lines and shapes and described as “undulating”.
Random rhythm in art refers to the random application of art elements; there is no order to how the sequences or patterns are placed in the composition.
Fall Plowing (1931) by Grant WoodLizard (1942) by M.C. EscherThe Great Wave off Kanagawa (1831) by Katsushika HokusaiThree Flags (1958) by Jasper JohnsAutumn Rhythm: Number 30 (1950) by Jackson Pollock