In the next  experiment, both CA interact continually. During each step CA-2 and CA-3 are added together, and the result  becomes a CA-4 state (CA-4 = CA-2 + CA-3).
In the following  experiment  CA-2 and CA-3 states are multiplied and the result becomes a CA-4 state (CA-4 = CA-2 * CA-3).

Since each CA cell  may exist only in three states (0, 1, 2), addition is in Mod[3].  The one time interaction created a new process which ultimately died. At a different time it might become a solution. The state resulting from a continuous interaction has no influence on the subsequent  CA state, which will be determined solely by the interacting CA. CA-4  may be regarded as a solution of two interacting processes.  

In the last experiment CA-2 starts as a non-interacting  process. Its structure is identical with the stem process, nevertheless it is transient, since interacting with other processes. When CA-4 = CA-2 + CA-3, and CA-3 exists, it modifies the CA-2 structure, and when dying,  CA-4 keeps the original CA-2 structure. When CA-4 = CA-2 * CA-3, parts, of CA-2 vanish and CA-4 oscillates.

Setup
solution[2, 25, 11]; solution[3, 25, 9];  If [ j == 14,  a[[4]] = a[[2]] * a[[3]]; go[100]; solution[2, 25, 11]; solution[3, 25, 9];  If [ j > 0,  a[[4]] = a[[2]] * a[[3]]; go[100];