I see the wheels spinning. A spark of crea-...-How do they get the lead in pencils?

我看见你的脑筋在转动。创意的火花...-他们是怎么把铅锌放进铅笔里的？

Among other things, it is the stuff used as the " lead" in pencils—hardly the highest of tech applications.

除其他外，它是用作铅笔“铅芯”的材料——算不上最高级别的技术应用。