A Sequence of Predetermined Actions
First, imagine there is a machine in front of you. Naturally, it begins to operate when you turn on the power.
Now imagine that the machine is more complex. When powered on, it performs actions in a predetermined order. The sequence and details of these actions are stored somewhere, and the machine operates by reading those stored instructions.
Next, what if we could freely define the order of these actions? Then the machine could perform Action A or Action B depending on our instructions.


