Staircase maneuver

The staircase maneuver is a tactical motif which tends to occur in queen and pawn endgames, where the defender has advanced pawns on the seventh . The tactic employs the idea of alternation, with the attacking queen alternating between black and white squares until it reaches an open file, where the opponent's queening square is not controlled by one of the opponent's pawns. Thus the attacking queen alternates between a series of pins and checks until it delivers the final mate.
Example.
In the diagram, if Black's pawn on b2 had already on b1, the game would be drawn. White mates in twelve, however, using the staircase maneuver: 