Connected passed pawns were under way
Please look at the pawn structure in the following diagram:
It came up in a game between GM Gligoric and GM Szabo in Helsinki 1952. I think you agree that this is a really rare one. White has two connected passed pawns on queenside and black almost the same in center.
Here how it happened:
Let us have again a look in advance ( move 27):
Well, this is not the complete position of move 27, only the kings, the pawnstructure and the minor pieces.
Here we see something very surprising. Not only that white passed pawns haven`t advanced anymore, but they are very well blockaded through the black knights.
In contrary, the black center pawns have made their way and are not blockaded through white minor pieces.
So what had happened?
Now started a phase of mutual errors. But it ended in following position:
White had started a kingside attack, but the center pawns looked very menacing.
The game ended in move 38 in following position
White attack had been stopped, but the black center pawns were unstoppable. Therefore white resigned here