Mass fraction of H, He, C, N, O, and Ne as a function of the mass coordinate for the donor star (star 1) and the accreting star (star 2) in rotational binary model B2. Different evolutionary stages are indicated by the different colors: the beginning of the first episode of RLOF (red solid lines), the terminal of the first episode of RLOF (green dashed lines), the beginning of the second episode of RLOF (blue dotted lines), and the terminal of the second episode of RLOF (purple dashed–dotted lines.)