Complexity Explorables is a website where people easily explore some complex systems examples while playing models with fun.
For example, “I herd you!” enables you to explore how different network structures impact the spread of a disease in a population. Consequently, you can understand a phenomenon called “herd immunity”, defined that “a disease can be eradicated even if not the entire population is immunized.” The webpage is simple, yet very informative.
If you’re interested, there are many other examples and models. Check them out at http://www.complexity-explorables.org/explorables/!