It is an adding circuit for binary numbers with input carry bit, which consists of two HalfAdders.
a.y, b.y and c.y are the inputs of the FullAdder.
cout = Or1.y and h.s are the outputs of the FullAdder.
t is the pick-up instant of the next bit(s) in the simulation.
a.y b.y c.y cout h.s t 1 0 0 0 1 1 0 1 0 0 1 2 0 0 1 0 1 3 1 1 0 1 0 4 0 1 1 1 0 5 1 0 1 1 0 6 1 1 1 1 1 7 0 0 0 0 0 8
The simulation stop time should be 10 seconds.