Festoon filling stitch
This pulled thread stitch forms a pattern which resembles a garland (hence the name, as a festoon is something which is hung in a curve). It is worked entirely in back stitch from right to left.
The name ‘festoon’ features in many stitch names: the Italian punto a festone is known as buttonhole stitch in English, although it literally translates as festoon stitch; the French point de feston is an alternative name for single Brussels stitch.
Bring the needle up at the top right of the shape to be filled, two fabric threads from the edge.
Bring the needle up two threads to the left and four threads down, and insert where the previous stitch emerged.
Bring the needle up two threads to the left and two threads up to start making a scallop shape.
Continue working back stitches following the festoon outline as shown in the diagram to form a garland pattern.
Structure of stitch
Mary Thomas’s Dictionary of Embroidery Stitches (1934) , p.96–7
Kate Haxell, The Stitch Bible (2012)