A system consisting of two components is subject to a series of shocks that arrive according to a Poisson process with rate λ. A shock can cause the failure of component 1 alone with probability p, component 2 alone with probability q, both components with probability r, or have no effect with probability 1−p−q−r: No repairs are possible. The system fails when both the components fail. Model the state of the system as a CTMC.