Fig. 3.

Evolution of codes in a rugged fitness landscape (a cartoon illustration).

r₁, r₂ ∈ r : random codes with the same block structure as the standard code

o₁, o₂ ∈ o : codes obtained from r_{1, r2} ∈ r after optimization

R₁, R₂ ∈ R : random codes with fitness values greater than the fitness of the standard code

O₁, O₂ ∈ O : codes obtained from R₁, R₂ ∈ R after optimization

The figure is modified from (86).