A network illustration describing the workings of the decoder at each step of the stepwise procedure. Activating interactions are represented by pointed arrows and inhibiting interactions are represented by arrows with flat heads. In (a), CRP-cAMP complex together with L-arabinose-araC complex activate expression of YFP from P
promoter under (-/+) condition. In (b),(c), (d), the networks at step 2, step 3 and step 4 are illustrated.