GOLD_BLOCK/GILDED_BLACKSTONE/BIRCH_PLANKS/OAK_PLANKS were also present
on a nearby backdrop wall in the user's build, so even with the
plane-locked diagonal fix (which only stops leaks through the ring's
thickness), the flood-fill could still sweep in decorative use of the
same materials sitting in-plane with the ring, putting chevrons on
unrelated blocks. Default is now just OBSIDIAN; anyone mixing
materials should keep the list to ring-only blocks per the updated
config.yml/README guidance.
Michael Burgess
980f73e7d2