Budding yeast model. (A) A subset of the Mangla, et al.’s model that highlights the second hazard. Since Clb2 is activated to the highest level, the activation of Cdc20 cannot activate Swi5. (B) The hazard can be eliminated by replacing the weights of reactions, from Cdc20 and Clb2 to Swi5, to stronger and weaker levels, respectively. Swi5 is also extended to have one of three eligible values like Clb2. (C) The final timing-robust model for the budding yeast cell cycle. Lines with blue are modified from the Mangla, et al.’s model.