A pawn Duo in chess are simply two pawns that are adjacent on a rank. Out of the opening, the pawn duo comprised of the d4 and e4 pawns arises in the French and Caro-Kann defenses. Advanced pawn duos rank very high in the evaluation of a chess position frequently being stronger than the proverbial WHOLE ROOK. So, quite obviously, the possessor of an advanced pawn duo would frequently be very willing to be down multiple pawns to have a pawn roller!
In the following position reached in 3 minute blitz game at the internet chess club, BigCol, a very capable chess player and helper at ICC, had to believe he was winning with Re7 check winning Black’s b7 pawn and threatening to advance his queen side pawns.
However, Black will win White’s indefensible g4 pawn creating an advanced pawn couple on the f and g files. This pawn roller will restrict the White King and combined with the Black Rook are “faster” and more effective than the White queen side pawns.
Observe that after White wins the b7 pawn, Black may also play Ra3, eschewing the creation of pawn couple, guarding the weak a7 pawn with excellent winning chances owing to his protected passed pawn at f4.