Count squares, get an instant verdict: no calculation needed.
Pawn advances. The square shrinks to 3-by-3.
3 more clean runs (at any point) to reach Recall.
White pawn on a4, Black king on h8. The pawn needs four moves to queen: draw a 4-by-4 square from a4. Black's king is outside it. Can it catch up?
3 more clean runs (at any point) to reach Recall.