A compound pulley is distinguished from a simple pulley in that the simple pulley is only able to redirect the force needed to lift an object, whereas a block-and-tackle rig is able to cut the force needed for the job in half.
Elevators use Multiple Pulleys in Order to Function
Examples of pulleys include: Elevators use multiple pulleys in order to function. A cargo lift system that allows for items to be hoisted to higher floors is a pulley system. Wells use the pulley system to hoist the bucket out of the well.
A movable pulley is a pulley that can freely move. This is only one of three types, the other two being fixed and compound pulleys. Examples of movable pulleys are elevators. Examples of movable pulleys are elevators.