Before beginning with the embroidery I added some triangles and cut outs of the remaining felt (to the right) to the background to make it more interesting.
I will begin with the embroidery after attaching these pieces like an appliqué with tiny stitches all around like you see in the second photo.
The surface was a felted piece of about 40 x 50 cm (15" x 16")
Each rectangle is about 8 x 12 cm (2 1/2" x 4")
The idea is to improve or use your imagery and your use of basic stitches for making the piece more interesting and to push your boundaries. The running stitch allows an infinity of uses on your work, just try new ones, different space between rows, thin and coarse yarns, one or two threads on one needle, changing direction, overlapping, etc.
Because we have many rectangles and we wish to do a wall hanging or book , we can practice different ways to use the same stitch in different rectangles, if this enhances the composition.