Maybe all art is slow art, which is why it is art and not graphic design. 1967, Richard Long, then a student: A Line Made By Walking — the smallest gesture in a drawing where there is only artist and surface; no paintbrushes, paint, equipment, frame. The surface is complex — grass and other little plants easily crushed, changing the nap of the field where Long walked back and forth until his path registered. Cognisant of Smithson and the American land artists of the 1960s, he, perhaps because British, a student and probably cash-strapped, made equivalent gestures in the landscape without all the heavy lifting of cranes, excavators and dump trucks. The restriction becomes the modus operandi for the rest of his career.
Here, a video: Making River Avon Mud Circle, M-Shed, Bristol 2011