Hertzsprung–Russel Diagram showing evolutionary tracks of the primary star in a binary system with initial masses 5, 6.5, 8, 10, 12, 16. 16.9, 20, 22, 26, 30 and 40 M_⊙ at LMC metallicity. The blue lines represent the mass transfer phase, and the orange lines represent the puffed-up stripped star (PSS) phase. Red dots represent the terminal age main sequence (TAMS), and the blue squares represent the end of core Helium burning. The green dots are placed at intervals of 20 000 years starting from RLOF. The clustering of these dots towards the left shows that the star spends a long time in this phase.