Meanings of the slides?

[here4uallday]

Hey guys,
If any of you could explain what each slide in Amnesia: Justine means that would be very helpful.
I'm just very confused by them.

[IsaacJGL]

I'm pretty sure you use them to murder people, I used the slides on the second kill in the two slots.

[A.I.]

They where to used on justine when she was young to see how her mind worked...but other than that I don't really know anything else about them