Определение кремния похожего на наконечник стрелы

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https://ru.wikipedia.org/wiki/%D0%9A%D1 ... D0%B9%2520(%D1%85%D0%B8%D0%BC%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B9%2520%D1%81%D0%B8%D0%BC%D0%B2%D0%BE%D0%BB%2520%E2%80%94%2520Si%252C,%D0%9C%D0%B5%D0%BD%D0%B4%D0%B5%D0%BB%D0%B5%D0%B5%D0%B2%D0%B0%252C%2520%D1%81%2520%D0%B0%D1%82%D0%BE%D0%BC%D0%BD%D1%8B%D0%BC%2520%D0%BD%D0%BE%D0%BC%D0%B5%D1%80%D0%BE%D0%BC%252014.