Hello there,

I present to you the ultimate device that determines whether a student has studied well or not. The main idea is pretty simple:

If not - they are scared to acquire the pencil, assuming that this is a feroucious and deadly animal, thus unable to continue the class and take notes.

If yes - they know that this is a python - nearly harmless and  cute fellow that's just holding their pencils.

Printing:

I recommend using the lightning infill, three to four perimeters and slim tree supports, as shown on the screenshot in order to save some filament.