This is my understanding as well. I found this video puts together a nice history lesson on how it changed forms and a little of the why as well. https://www.y

This is my understanding as well. I found this video puts together a nice history lesson on how it changed forms and a little of the why as well. https://www.youtube.com/watch?v=OMVfrvsIfAo&feature=youtu.be https://www.youtube.com/watch?v=OMVfrvsIfAo&feature=youtu.be