Before reasoning from a guess, long-press to plant a 📌. In the picture the pinned cell is assumed to be a ghost, and the chain crosses out the three yellow cells — which clashes with the pink-framed column that still needs one ghost. When the contradiction comes, walk back to the pin and write the opposite. Memos record conclusions; pins record thinking in progress.

In the app, one new tip arrives for each day you play.

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