the latent variable you can use this type of model as a forward model in a control system where you have the state of the world the action you take whether you turn the wheel without your accelerator brake you run this to your forward model gives you the next state it takes a random sample from the latent variable to make that prediction you can read this multiple time steps there's a cost function that measures if the car is in lane if it's too close to other cars it's differentiable so by back propagation you can propagate gradient