Step 7 of 8
Count a satisfied pillar
A pillar that has its torches is a "0" in disguise: no more torches beside it.
The rule of thumb: A numbered pillar with all its torches placed marks the rest of its neighbors X.
A numbered pillar that already holds all the torches it asked for is done giving. Every remaining neighbor gets an X — the quiet counterpart to the "0" pillar: not "no torches" but "no more torches". Make it automatic the moment a count is met.
Satisfied pillars are anchors. Their X’d neighbors narrow the candidate sets of nearby dark rooms and the open counts of neighboring pillars, which is often what finally forces the next torch. These practice boards are chosen so that skipping the count leaves them stuck.
Where to look: Pillars whose placed torches match their number. Recheck them after every placement near them.
Worked example
A real position from a board that needs Count a satisfied pillar. Purple: what the reasoning rests on. Dashed: the cells in question. Green: what it proves.
One more count: the pillar still waiting for torches it can’t avoid. Step 8: Count a hungry pillar →