Once upon a time there was a little boy called Hansi and his sister Heidi. In a cold dark November evening they walked through a dark and scary forrest. They got deeper and deeper in this forrest. And finally they hadn't any idea where the way back out may be. While crossing a green meadow with lots of rotten mushrooms they met a raven with a golden bill. For a while they followed the bird. But then the bird disappeard and the children were even deeper in the woods.
They came to an old house where an old witch lives. The old lady invited the two kids to come in and get something to eat. After a delicious dinner they all went to the witch's computer room, where three PC are connected to a cute little local area network. All together they had fun playing doom all night thru. Suddenly the kids realized that the whitch was a cyborg, an artificial old lady. And Hansi said to his sister: "Look! She has a plastic back!"
Of course that's not the story of the invention of plastic bags. The real story is very interesting and fascinating. You should read about it. But as you know the plastic bag is a German invention. And so this story is a German story. Unfortunately it is not translatable. It only can be told in German language ("which is the way He (God) talks whenever it is heavy business" (Frank Zappa).
You should know this story! So you should learn German!