Discuss PGroot's answer to: Can you use Silly Putty to copy a test?

Silly Putty will take impressions from newsprint, or at least it used to before they changed inks to use soy.  Probably it won't work well on the printing from an office copier.  And if you want to copy with Silly Putty, you would have to stretch it out, take an impression, and print it onto another piece of paper, without the teacher noticing.