Click on the start button to see 100 iterations of the quadratic map,
for each value of the grows constant, r. The iterations are started with x = 0.5. After that, the first 300 iterations are discarded and the next 100 are plotted.
You can zoom in on the bifurcation diagram by specifying the limits of the r- and x-intervals. You can either type these into the text fields or you can drag the mouse inside the plot area to accomplish this.