Feature space projected on the first two principal components (PC₁ on the x- and PC₂ on the y-axis). Each symbol represents a mock observation, obtained from a snapshot. Groups of symbols correspond to simulation runs and are labelled according to the name of each run. Empty red symbols correspond to merger simulations, filled black symbols to monolithic simulations. It appears that PC₁ correlates with the initial dimensionless potential W₀ of each run.