The process involves cutting out patterns of objects, like the striped fish, into primary elements or segments. These separate pieces then have the edges rounded over and the surfaces occasionally contoured. Then a pigmented color is applied to the individual segments. Finally, the segments are reassembled with glue to re-create the whole. Many finishing or painting options can be used.
Segmentation is easy, fast, and inexpensive.
Projects use simple materials that are colored to suit the whim of the maker. Intarsia is art. This book gives a quick primer of how to do it and then some examples of the simple through the more elaborate. My interests are not in country craft so my bias about this book is mostly negative, although the Umbrella People are cute. Nevertheless, at the end the rose project mentioned above is presented to give inspiration to all of us.