Illustration of a time-dependent vector field (indicated by the gray arrows) continuously transforming samples from a standard 2D Gaussian at t = 0 into samples from a more complex, star-shaped distribution at t = 1. For simplicity, we show an unconditional example here; for an atmospheric retrieval, the vector field would depend not only on t but also on the observed spectrum x, and the assumed noise level σ. The size of the arrows has been rescaled for visual purposes.