However, many details of shape and pattern are not interesting. A particular object can disappear from perception and reappear again. The location of an object in the world is more persistent than its location in the visual field. There are many continuous processes with intermediate states in addition to moving objects. The environmment of a child contains other people, usually including a mother, and parts of people including parts of the child itself.
Objects often have parts which are objects.
However, often only some of the parts are separately identifiable. The boundaries of the parts are often not definite. Some are rigid and some are flexible. Babies are ready very early to learn what kinds there are. At least some ternary relations such as betweenness are basic.