Examples of LMC first-overtone mode Cepheid binary candidate O–C diagrams over-plotted with their MCMC binary fit solutions (left). The blue dashed line represents the orbital solution obtained from the median parameter values of the posterior distribution. The purple-shaded regions imply one, two, and three standard deviations of the resulting MCMC fit in increasing transparency order. Above each panel the OGLE-ID, adopted pulsation period to construct the O–C diagram and the orbital period are shown. Same as above but for SMC first-overtone mode Cepheids (right). The remaining sample is presented in the appendix.