Who carved these many-sided rock columns?
这些多边形石柱是谁切出来的？
一根根石柱紧紧排在一起，顶部常常像拼好的六边形地砖。
Rock columns stand tightly together, their tops often resembling fitted hexagonal tiles.
在美国魔鬼柱国家纪念地，可以看到这样的景象。
You can see this at Devils Postpile National Monument in the United States.
它们并不是石匠切好后竖起来的，而与一大片熔岩慢慢冷却有关。
They were not cut and erected by stoneworkers; they formed as a large body of lava cooled.
关键的变化，发生在熔岩已经变成固体、却仍然很热的时候。
The crucial change happens after the lava has become solid but is still very hot.
岩石继续降温，体积收缩，也就是占的空间变小。
As the rock cools further, it contracts, taking up less space.
收缩产生的拉力使岩石开裂，裂缝从冷却的表面向内部发展。
Tension from contraction cracks the rock, and the fractures grow inward from cooling surfaces.
这些裂缝把原来连成一片的岩石分成柱状部分，称为柱状节理。
The fractures divide what was a continuous rock mass into columns, a structure called columnar jointing.
六边形很常见，但大自然没有要求每根柱子都必须有六条边。
Hexagons are common, but nature does not require every column to have six sides.
这种结构中也能出现三边、五边或七边的柱子。
Columns with three, five, or seven sides can also occur.
柱子的方向还与冷却表面的方向有关，所以不能把所有石柱都想成笔直向上的。
Column orientation also relates to the cooling surface, so they should not all be imagined as standing straight upward.
不过，形成石柱和让人看见石柱，是两件不同的事。
Forming the columns and exposing them to view are two different processes.
在魔鬼柱，后来经过的冰川移走了部分岩石，露出石柱，还磨光了部分柱顶。
At Devils Postpile, later glaciers removed some rock, exposed the columns, and polished parts of their tops.
眼前整齐的岩石景观，因此保存了两个阶段：热岩冷却时开裂，冰川经过后显露。
The orderly scene preserves two stages: hot rock cracking as it cooled, then being exposed by passing glaciers.
