Tap: It uses Levers. In order to activate it, we have to pull up the "head" then water will flow out from the tap.
Correction Tape: It uses gears. The gear on the left will be loaded with the tapes. As you use you, the one on the right will then collect the used tape. This is how it will work.
Scissors: The scissors is a first class lever. You place your hand on the handle (The red part) and place the thing that you wish to cut on the other end. It is like E-F-L.
It is very hard for me to lift up the cover when I want to change batteries for my alarm, So using a lever it will be much more easier to lift the cover up.