particular model which is this this sort of chain structure there are two ways to view it you can just view it as a via e with this block of latent variables as just one latent variable and then you can run bits by B ba and s1 and then that works perfectly fine but another way to view it is to view it as a leak variable model with just a little just draw the layers again so here's X 1 Z 2 3 so you can just view Z 1 as the one and only latent variable but then you see that it's prior is a VA with the same structure so it's prior is P of Z 1