This graph is part of Chapter 4: Text and Labels. It is created by the script in the section entitled “Hypertext Labels”, which creates an SVG file with embedded labels that appear when you hover over the plotted dots with your mouse. Most recent browsers support SVG images; if you are using an older or unusual browser, you may see nothing here, or the interactive features may not work. Also, as the mouse interaction is controlled by javascript embedded in the image, this may not work if you have javascript turned off.