In ancient times, when thread and yarn were rare and precious and you were eager to have as much as possible of it shown on the front side (and not to waste it on the back side), the Bayeux stitch was often used for covering the surface of a fabric in a decorative way.
This stitch is actually an old Anglo-Saxon variation of laidwork: on the front side, it ressembles satin stitch, but instead of letting the yarn pass across the reverse side, the thread is brought back up to front again very close to where it went down. A second layer is then sewn in intervals at a right angle to the first layer and held down with a short stab stitch.
All these three elements can be done with the same or with different yarns.
It's really quite simple to learn and gives a variety of possibilities in shading colours and effects through the different layers. (A useful link for working out the bayeux stitch is this pdf-tutorial by Jan Messent herself, presented by The Embroiderers' Guild.)
Here I've tried a fragment of it, using self-dyed mouliné for the bottom layer, a thin cotton thread (hand-dyed too) for the vertical layer and for the outline stitch, and finally a metal thread for the couching stitches.
My inspiration for this fragment had its origin in this posting of my friend Elizabeth/Landanna in Denmark, where she presents a wonderful book of Jan Messent, "Celtic, Viking & Anglo-Saxon Embroidery".
(Here you have another link for having a further look into the book.)
(German summary: Dieses Fragment zeigt den Bayeux-Stich, ein sehr alter angelsächsischer
Stich, der eine Art Kombination und Variante des Plattstiches mit dem Überfang- oder Bucharastich ausmacht - damals eine wirtschaftliche Notwendigkeit, heute auch eine vielseitige Gestaltungsmöglichkeit.
Bitte folge auch den links oben zu dem Buch von Jan Messent und zu meiner Freundin Elizabeth, die mich erst darauf aufmerksam gemacht hat!)