The stones are reduced to a small size by the constant attrition:

He was learning all about humanity by constant attrition with mankind.

Hell no, we were just at start of a process of constant attrition.

And yet, withal, some ideas, by constant attrition, had acquired a really striking form.

Yet the Russian wearied in the constant attrition, and top seed Djokovic cruised to victory, having passed easily his biggest test at the tournament.