The Coevolution₁ rule has a performance of 85.1% and was discovered using a coevolutionary approach between GA-evolved rules and ICs [8].

Gene expression programming found the solution to the Coevolution₁ rule in four phases. Firstly, chromosomes composed of nine genes of length 22 each were used. The sub-ETs were linked by IF, forming a huge multi-subunit ET. An intermediate solution with fitness 121 was found after 47093 generations of a small initial population of 30 individuals. Then, this intermediate solution was used as seed, and after 11785 generations a better solution with fitness 123 was found. Then, the genes of this intermediate solution were increased from 22 to 34 and populations of 50 individuals were left to evolve for 50000 generations. On generation 37362 an intermediate solution with fitness 127 was discovered. Finally, this program was used as seed to create another population, this time with 50 individuals. After 15189 generations the following perfect solution to the Coevolution₁ rule was found:

where the sub-ETs are linked 3-by-3 with IF, forming three big clusters that are, in their turn, linked also 3-by-3 with IF.