the See-Saw makes use of 2 springs as a fulcrum so that it will go back to its original position after use and to make the see-saw riding more smooth. The see-saw is a first class lever. It has a pivot in the middle and the load and effort on the opposite ends.
The scissors is a first class lever with the fulcrum in the middle and the load at the 2 blades and the effort applied at the 2 handles. The scissors is used to cut through things like paper with a very little amount of force.
Photo 3-Correction Tape:
The correction tape makes use of 3 gears which attaches to the cartridge to rewind the used tape as it is being used back into the cartridge. The cartridge is a kind of chain and sprocket. The tape is the chain and the two sprockets work together with the gears to move in unison.
In the photo the lamp makes use of linkages to connect the head of the lamp to the base and the power source. The linkages also act as a support to keep the lamp standing upright. The linkages also allows the lamp to change positions to allow for greater flexibility in where it shines the light.