The advantage of the mound fire is that it can be built on flat exposed rock or on an organic surface such as litter, duff or grass.

堆火的好处在于它既够在平整暴露的岩石地面进行，又可以在象干草落叶一样的有机物轮廓进行。

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They'd balance a spoon-shaped piece of magnetic rock on any flat surface, and since it was magnetic, the handle would swivel to align itself with the Earth's magnetic poles.

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