To help dry the paper, the mold lets the water flow through the small wire squares.

VOA: special.2009.07.06

You've got to pretty much take that chalk, and make a slurry out of it, put water, and dry it back up, put in a mold, and then you can have the chalk again, but you can't just glue it back together.

你得尽可能地收集它的碎片，把它做成粉浆，加水然后风干，放进模具，然后你就能重新得到这支粉笔，但是你不能简单地把它粘起来。

麻省理工公开课 - 热力学与动力学课程节选