look like you have some bit stream B on the left here so that's where you start out with then what happens next is you want to compress it and end up with a compressed version of that bit stream and the hope that that compressed version has lost its anatomy original so when you send a compressed extreme over a channel or stored on a hard drive or whatever you want to do with those bits in a more compressed way then it's ideally a lot less good but then when you want to use it later you should be able to expand it back out just the