Graphical model representation of the evolving means model, modelling the conditional distribution P(v_ϕ |[M/H]) with a two-component GMM, where the means and standard deviations are fixed (left) and varying (right) with respect to the underlying metallicities. The evolving or varying means model is also implemented for circularity as the conditional distribution or P(η |[M/H]). The subscript 1 and 2 stands for the disc-like and halo-like components, respectively, with μ and σ as the Gaussian mean and standard deviations in v_ϕ or η, conditioned on the value of [M/H]. w stands for the relative contribution of the disc-like component with the relative contribution of the halo-like component defined as (1−w). A list of the model parameters and their priors and functional forms are given in Table 1.