A carved rosette is either convincing or it is a wooden button, and the difference is that it is made in two layers.
Cut a flower from a single thickness and every petal springs from the same plane, which is not how a flower works. So our artisans carve the under-layer first - the broad outer petals, laid back and shallow - and then carve a second, smaller layer of inner petals from separate stock and set it into the centre, rotated so that the upper petals fall between the lower ones rather than on top of them.
That rotation is the whole trick. It is what puts a real shadow between the two rings of petals, and it is why the flower keeps its depth when it is gilded and everything becomes one colour.
The centre boss goes in last, sitting slightly proud, so there is a highlight at the middle of each rosette that the eye finds immediately from across the room.