The logistic equation is a famous simple nonlinear model (try this link for some information on the logistic equation).
The initial image in the applet has values for lambda ranging from 0 to 4 along the bottom, and the values of x from 0 to 1 up the side. The moving dots represent the changing values x takes for each value of lambda as the function is iterated. The brighter the dot, the more recent that value of x was taken by the function.
With the "Zoom In" check box ticked, click and drag with the mouse in the image to zoom in on a particular area of the graph.
By unticking the "Zoom In" check box you can click and drag a region into which the graph will shrink. The initial image is the maximum zoom out possible.
The logistic equation applet was programmed by Alexander Kasprzyk in December 1998.