Evolution of principal axis ratios of the simulated clusters with age. The areas shaded in light colors enclose the minimum and maximum values from bootstrapping as a function of time, for intermediate-to-major axis ratio b/a (upper row), the minor-to-major axis ratio c/a (middle row), and the minor-to-intermediate axis ratio c/b (bottom row). Columns show the results of the different models (indicated at the top). The colors of the shaded areas indicate the bootstrap range for models with different ω₀. Symbols with error bars indicate the principal axis ratios for observations calculated from the members of the star clusters studied in Pang et al. (2021, 2022b, 2024).