October 26, 2021 What could possibly be better to see than an upward trending spark chart? How about one in 3D? With this financial charting tool, you get a year-to-year comparison of daily stock performance charts. There are 252 trading days on the x-axis for each year, and 20 years on the y-axis, resulting in a three-dimensional surface plot. This chart shows the history of the stock performance of General Motors. Click and drag to rotate interactive chart.