Figure 4.

Local search results. Summary of the effects of adding one (giving 32 grammars) or two (giving 961 grammars) production rules to $\mathrm{KH}99^{\prime }$. The plot shows the cumulative proportion of grammars with given sensitivity. The grammars’ sensitivity is mostly still equal to the sensitivity of $\mathrm{KH}99^{\prime }$, with only a few outliers. GG1 was the top outlier for two production rule added. In this sense the space is reasonably flat.