Prograde dipole mode frequencies for the 3 M_⊙ reference model, with the X_c values of our model grid (Sect. 4) indicated with orange dashed vertical lines, and the rotation profile (ℛ_rot = 0.25) indicated in the inset on the top left. Radial order boundaries are indicated in the near-ZAMS zoom (bottom left), as well as the X_c values for which period spacing patterns are extracted (right hand column). That panel also shows an observed frequency crossing. Specific modes and spin parameters are indicated in color, and the color scheme for the period spacing patterns is the same as in the top right panel of Fig. 2.