# “Anomalous Itinerary”

## Lévy flights

This explorable illustrates the properties of a class of random walks known as Lévy flights.
To get the most out of this explorable, you may want to check out the explorable **Albert & Carl Friedrich** on ordinary random walks and diffusion first.

# “Albert & Carl Friedrich”

## Random Walks & Diffusion

This explorable illustrates the geometric and dynamic properties of the physical process of **diffusion** and its intimate relation to a mathematical object known as a **random walk**. It also illustrates graphically the implications of the **central limit theorem** that explains why we so often (* normally*) observe

**Gaussian distributions**in nature. In the context of random walks this means that in the long run and from a great distance the paths of different types of walks become statistically indistiguishable.

# “Kelp!!!”

## A stochastic cellular automaton

This explorable illustrates how fractal growth patterns can be generated by **stochastic cellular automata**. Cellular automata are spatially and temporally discrete dynamical systems that are conceptually very straightforward but can generate unexpected complex behavior, often fractal-like structures reminiscent of patterns we see in natural systems.

# “Barista's Secret”

## Percolation on a lattice

This explorable illustrates a process known as percolation. * Percolation* is a topic very important for understanding processes in physics, biology, geology, hydrology, horstology, epidemiology, and other fields.

*is the mathematical tool designed for understanding these processes.*

**Percolation theory**# “Critical HexSIRSize”

## The stochastic, spatial SIRS model

This explorable illustrates the behavior of a contagion process near its *critical point*. Contagion processes, for example transmissible infectious diseases, typically exhibit a critical point, a threshold below which the disease will die out, and above which the disease is sustained in a population. Interesting dynamical things happen when the system is near its critical point.