If you look up the inlay term it will give you a better idea, it is a technique done in wood or stones traditionally. Inlay is only on the surface and it is flushed with the rest:
in·lay
verb
ornament (an object) by embedding pieces of a different material in it, flush with its surface.
"mahogany paneling inlaid with rosewood"
noun
/ˈinˌlā/
1.
a design, pattern, or piece of material inlaid in something.
"ivory inlays that decorated wooden furnishings"
2.
a filling shaped to fit a tooth cavity.
Embeds usually stick out more or go through the whole soap bar