I am starting to work on the shaped felt now. Above is a sample, made years ago, based on a dry stone wall in The Lake District. I remembered it when thinking about my felt rocks and planning how to work the embroidery. I was amazed to see the intricate tiny stitches I produced at that stage.
I bubbled up some synthetic organza using a heat gun and painted scraps to be my ice and lichen round the rocks. Tiny stitches, Chinese or Pekin knots. I read somewhere that people went blind working these - I can well believe it.