The surface of both sides has beautiful ripples and, when you look closely, you can see that these are the scars from its making, where the flakes of the flint have been carefully chipped off.

细细观察下来，就可以看出那是打磨过程中留下来的。 当年工匠精工细磨，慢慢地在这燧石片上敲下片片碎石，就留下了道道的痕迹。

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To torment the players further, the USGA shaved down the banks below seven of the greens, so that balls that just barely miss the putting surface, or are chipped just a smidge too hard, can sometimes race 10 to 20 yards away.

WSJ: 2012 U.S. Open: An Olympian Effort Just to Survive