Worden Blocks is a fun and useful tool.  It is very easy to build and customize charts, indicators, and scans.  Here is an example of something built with Blocks.  It is a composite index of the five major US equity indices (Dow, S&P, Naz, Russell 2K, and MidCap).  On the version I use, I also have a tool that shows the percent change from any date to any other date.  I marked two of them on the chart below.