埃莱玛随手捡起一块这样的工具展示给我看：一块上好的黑色玄武岩石块，四周已经被打磨成薄片，但锥形的尖端部分已经缺失。
Elema picked one up to show me: a handsome hunk of black basalt that had been flaked on all sides, missing only its tapered tip.
一与外空心螺钉的盲孔道相匹配的内螺栓，内螺栓的尖端部位亦为锥形，尾部设有螺纹和供握持用的四方体。
The top part of one inner bolt which matches the blank hole channel of the outer hollow screw is also conical. The rear is provided with a thread and a tetragonal body for holding.
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