One of the first psychologists who in the early twentieth century used the coloring mandalas as a relaxation technique was Carl Gustav Jung. He prescribed his patients coloring mandalas as part of the therapy.
Images for older children may already contain small parts, complex narrative compositions with greater color palette. The outline is more subtle. These can be supplemented with coloring tasks. For example, to write the missing word, or paste a sticker, finish drawing, connect the dots.