Complexity does not require a designer. It emerges from agents responding to local cues in their environment.
Paper wasps build intricate nests without a plan. Each wasp follows local rules: if a surface looks like this, add a pellet of wood pulp. This coordination through the environment is called stigmergy.
Builders walk randomly. When they encounter a pattern that matches their rules, they deposit a block. Arches and chambers emerge from a simple foundation.
Let a few chambers form, then damage the nest. The wound stays marked so repairs can be read directly from the simulation.
Figure 1. Stigmergic construction in action. Builders read local neighborhood patterns to decide where to place blocks; a damaged patch exposes the same edge patterns and becomes a repair experiment.
Different rules produce different structures.
Figure 2. The construction rule set. Brown is solid, white is empty, gray is "any."
The damage button above turns self-healing into an experiment rather than a claim. It removes a compact patch from whatever structure has grown, keeps those cells outlined in red, and reports how many have been rebuilt. The repair does not come from a blueprint; it comes from fresh broken edges satisfying the same local rules that built the original nest.