How do the inner mechanics of a vending machine work?

Saw one yesterday. I think this is how it works.

Inside the vending machine, the items are organized in some kind of shelves or rack, or whatever you want to call that. Items are organized in that.

Next thing we know that there's some kind of "lift" that will work and pick up the thing that you want. The "lift" will move up and down, left to right. and then drop the thing to the box where you pick it up. of course behind the rack of every column of item, you can find some kind of centrifugal stick that will give a force enough to make one item to be pushed into the lift.

Well, this is my analysis after seeing an open drink vending machine yesterday.