random bits then you get a sample and then the next thing the encoder does is it encodes X using this using P of X given Z which is actually called the decoder and then it finally encodes e ok so what actually happened here so if we just visualize this in a spit stream like this so so that this is what we started off with in the first phase when we decode Z we actually remove a little bit of this bit stream from the right so imagine this is a stack where we keep adding things on the right so in this first phase we remove a little bit and