Spin period (P) plotted against the orbital period (P_orb) of the simulated pulsars. The red circles with a black outline are the AIC WD that became recycled pulsars, while the other points represents recycled pulsars formed via core-collapse supernova with either a HeWD or COWD companion. The four regions, labelled I, II, III, and IV, represent the same cut as in Tauris et al. (2013) to explain their differences as an evolutionary point of view.