How can you classify iron and aluminum?
Iron cans stick well to the magnet. However, aluminum cans do not stick well to magnets.
If the last wheel of the conveyor belt is magnet, the iron cans is sticked to the magnets as long as possible.
On the other hand, aluminum cans do not stick well to magnets. Aluminum cans fall directly from the end of the conveyor belt.
What if you do this with human hands?
This simulation tells us something very important. It means that you can work with high efficiency even if you do not put a lot of labor. And when you want to automate a task, you may not need that complicated process.