to the exact spatial locations than the parameters and overall topology, and justified our use of a smaller number of trials in subsequent experiments. Typically, assuming a normal distribution of width $\sigma = 0.1$, we needed $n=(2\sigma\!\cdot\!1.96/0.05)^2\simeq60$ trials to reach a 95% confidence interval of length 0.05, and 5 trials for a length 0.17. For practical reasons of computing speed, we chose the latter.

#### Sensitivity to update scheme

On the other hand, the emergent urban patterns depended on the number $n$ of cells filled at every iteration, before land values were recalculated at the next iteration, i.e. whether the update scheme was a sequential ($n=1$) or parallel ($n>1$). Building several houses “simultaneously” between two market reevaluations is consistent with the view that real-world functions have a response delay, here of the order of $\tau$. There must be a limit, however, and an intermediate $n$ must be found to obtain reasonable simulations.

To this aim, we explored the 4D parameter space of the $\alpha_k$’s as in Figs. \[fig\_morpho\]-\[fig\_influences\] and ran one sequential update scheme and one parallel update scheme with $n=20$ in each case. At the end of the simulation, $t=T$, the two corresponding output patterns $\delta_\mathrm{seq}$ and $\delta_\mathrm{par}$ were 