Number of stars of certain types alive at each time, normalised by the total initial number of stars generated in a synthetic cluster for the case of a burst of star formation at t = 0. The solid lines represent stars computed with the Schwarzschild criterion, and the dashed lines show the same for the Ledoux criterion. Top panels: blue and red supergiants. The vertical axis is logarithmic, and the time axis extends to 60 Myr. Bottom panels: Wolf-Rayet stars. The vertical axis is linear and in units of 10⁻³, and the time axis extends to 12 Myr (there are no WR stars later on). Left panels: non-rotating models. Right panels: rotating models.