Remember The Ideal Mechanical Advantage (IMA) of a pulley system is equal to the number of Load Bearing Sections of Rope (LBR). The system on the left has IMA of 1. The system on the right has an IMA of 2
An IMA of only 2, BUT . . . it has a Direction Advantage.
IMA = 3
Hard to tell, but this system has an IMA of 4
Block and Tackle system gives a large IMA. This one has an IMA of 8 with a direction advantage. Oh, but the price you pay, In order to get the load to lift 1 foot, you would have to pull out 8 feet of rope.