Following that list of affected gates at G3 is computed using the list of the gates driving it (namely, G1 and G2). For example, under s-a-0 fault at I1, OG1=0, OG2=0 and OG3=0 (while under normal condition OG1=1, OG2=0 and OG3=0); this is captured by affected gate marked I1 0 in the list of for G3. Similarly, for the other five faults (i) s-a-0 at I2, (ii) s-a-0 at I2(G1) , (iii) s-a-0 OG1, (iv)s-a-0 at I2(G2), (v) s-a-1 at OG2 , there are five gates in the list of G3. Also, another gate for s-a-1 fault at OG3 is added to the list making the number of affected gates at G3 to seven.

G3 drives driving primary output O1 and in the entire list of affected gates, output signal is 1 for (i) s-a-0 at I2(G2), (ii) s-a-1 at OG2 and (iii) s-a-1 at OG3, while in the normal gate output is 0. So input I1=1,I2=1 detects these three faults at O1.

It may be noted that only three gates correspond to faults being detected at OG3 (or primary output O1). So what is requirement of seven gates in the affected list? It may appear that deductive fault simulation, which keeps information about only these three faults (see Figure15) is better choice than concurrent fault simulation. The answer comes if we consider then >> random pattern as I1=0, I2=1. In case of deductive fault simulation we need to repeat all the steps, while in case of concurrent simulation we will re-compute only the information that changes as a result of changes in signals triggered by I1 (from 1 to 0). Now we will see the steps involved in the example of Figure 17 when input changes from I1=1, I2=1 to I1=0, I2=1.

Figure 18 illustrates the case when input I1 changes from 1 to 0. It may be observed that due to change in I1, signal in both the normal gates and the ones in the affected list change. For example, in gate G1, first input changes from 1 to 0 and also OG1 changes from 1 to 0. Also, the first input in affected gates I2₀ and OG1₀ change from 1 to 0. After these changes signal values in the affected gates I1₀ and OG1₀ become same as that of the normal gate G2. So affected gates I1₀ and OG1₀ are deleted from the list. Similarly, signals in affected gates I1₀, I2(G1)₀ and OG1₀ become same as that of normal gate G3; such gates are also deleted. It may be noted that some (affected) gates remain which has signal difference compared to normal gate even when input changes to I1=0,I2=1; for example, I2₀ remains in the list of OG1