Some products moves along with another product e.g. HSIV5 and HHIV5. When they don't moves along, it might indicate something is happening.
In the following chart, Spark plots the price of HSIV5 on the Y-Axis and price of HHIV5 on the X-Axis. Normally, the point represented by (X = HHIV5 price, Y = HSIV5 price) will move in a diagonal line when the market is stable.
A red section of the curvy line is where price is falling, whereas a blue one indicates a rising period.
The while circle marks the market start and yellow circle marks the current prices point.
The following plotting is done by smoothing over 15 points of 1-minute each period.
The following is the same chart but using a smoothing over 7 points of 1-minute each period. You can alter the smoothing factor yourself to filter out the "noises" in the chart.
In today (Oct 22, 2015), the market is very quiet and the X-Y chart is mostly a narrow diagonal line with only 30 points in vertical width, meaning the HSIV5 vs HHIV5 relationship is very stable.
See next feature: Option Implied Volatility Chart