The examples in this chapter suggest that if the rules for a particular System are sufficiently simple, then the System will only ever exhibit purely repetitive behavior. If the rules are slightly complicated, then nesting will also often appear, But to get complexity in the overall behavior of a system one needs to go beyond some threshold in the complexity of ist underlying rules. The remarkable discovery that we have made, however, is that this threshold is typically extremely low. [...] One might nevertheless have thought that if one were to increase the complexity of the rules, then the behavior one would get would also become correspondingly more complex. But [...] this is not typically what happens. Instead, once the threshold for complex behavior has been reached, what one usually finds is that adding complexity to the underlying rules does not lead to any perceptible increase at all in the overall complexity of the behavior that is produced.