A recent discussion on the Felting and Fiber Forum reminded me of a technique I haven’t used for a while, it relies the quality of some coarser wools to migrate through (engulf) finer wools, Gotland is a good example of this.
The pattern on the finished cave before shaving, the Gotland has engulfed the merino except where the plastic resist was placed (even there it has tried to migrate over the merino (it really is the Japanese Bind Weed of the wool world):
And after shaving:
This is the resist and the finished cave, it shrank just a little during the fulling!