Upper panel: visual representation of a cloud of solutions (sets of parameters) in 3D space of objective functions, advancing from initial population state (red) towards approaching the trade-off surface (black). Lower panel: representation in the parameter space via pairwise corner plot. Solutions that are close in the objective space (i.e. have similar χ² values) do not have to appear close in the parameter space, while those close in the full parameter space should appear close in the objectives space if the parametrisation is continuous.