 The analysis of bad norms isn’t just limited to cases where the norms in question are clearly the culprit in bringing about bad outcomes, though. Game theory can also tell us about the ways in which seemingly innocent norms and preferences can give rise to bad outcomes. Perhaps the most famous example of this is Schelling’s (1971) model of segregation which helps illustrate why segregation can be so difficult to combat. Schelling showed that even when agents don’t mind living alongside members of other groups, even very minimal preferences for having some neighbors like oneself can lead to individuals sorting themselves into relatively segregated communities over time. For example, Figure 15 below shows how a group of individual agents randomly distributed around a grid will segregate themselves over time when individual agents have preferences for being surrounded by certain thresholds of neighbors like  them.[21]  Here Figure 15a depicts a random initial distribution on a \(20\times 20\) grid, where 10% of squares are empty in order to facilitate movement, and there are two types of agent in equal proportion to one another. Figure 15b depicts the sorting that occurs if agents prefer to be surrounded by neighbors of whom at least 20% are like them. Figure 15c shows how things change when the threshold is increased to just 30%. And Figure 15d shows what things are like when the threshold is 50%.