This Demonstration implements point and figure (P&F) charting of stock prices. Before the advent of modern stock charts, P&F charting was a traditional charting technique. It is still very popular today because it is very simple to maintain by hand and reduces a stock chart to its most compact form, making it much easier to search for patterns in price behavior.
The charts are drawn using the traditional box sizes and three-box reversal, but the controls let you coarsen the chart by setting the controls to the right (i.e. making the reversal and box sizes larger and making the chart less sensitive to price movements). In particular, note that choosing both controls to be at the left, the chart appears very much like a regular stock chart. The blue trendlines represent support/resistance lines for the price of the stock. If you click the "show hint" checkbox, a tooltip appears that relates the position of a given column of x's or o's to the price history.