1. A method of drawing a pie chart with slices, each of which has an area proportional to the value of one datum of a group of data, on an Internet web page made visible on the display of a computer by illuminating pixels of the display, comprising storing in a pie definition array in computer memory representations of subsets of said pixels, the pixels in each of said subsets forming a horizontal line, the horizontal lines of all of said subsets collectively approximating the appearance of a pie when their pixels are illuminated on said display, for each slice, identifying all segments of each of said horizontal lines containing adjacent pixels to be included in said slice, and for each slice, illuminating the pixels in each of said identified segments to impart to said slice an appearance different from the appearance of all slices immediately adjacent thereto.