What is a block and tackle?
Is a system of two or more pulleys with a rope threaded in between the two. It is used to lift or pull heavier loads.
The use of the pulleys provides a mechanical advantage and reduces the required force needed to move a heavier load.
This makes it possible to double, triple, quadruple or even quintuple the capacity of a system by using the pulleys.
To generate the mechanical advantage, at least one pulley must be attached to the load.
View the diagram examples to help set you up: