with now we can do other things the same ideas we can use to find pairwise posteriors for example the posterior between XT and XT plus 1 jointly with all the evidence from what we derived on the board it should be clear what's going to happen here XT and XT plus 1 sitting next to each other we're going to work our way from the front and the back towards them and we're gonna stop right before each one of them coming from each side and then multiply in the middle the conditional XT plus 1 given XT and the evidences for that time slice