Mr. Shine chuckled. “To study the enemy, you have to get under his skin. When you’re under his skin, you start to see the world through his eyes. Gabbro is so good at playing from the dwarf viewpoint that his troll game is suffering, and he wants to go to Copperhead to learn from some of the dwarf thudmeisters there. I hope he does; they’ll teach him how to play like a troll. None of these lads here were out getting fighting drunk last night. And thus we wear down mountains. Water dripping on a stone, dissolving and removing. Changing the shape of the world, one drop at a time. Water dripping on a stone, Commander. Water flowing underground, bubbling up in unexpected places.”
“I think you’re going to need a bit more of a gush,” said Vimes. “I don’t think a bunch of people playing games is going to break down a mountain anytime soon.”
“It depends on where the drops fall,” said Mr. Shine. “In time, they may wash away a valley, at least.”

– water dripping on a stone |
Terry Pratchett, Thud!