The scatterplot matrix is designed to display the relationship between all pairs of several variables. The plot matrix consists of plotcells containing little scatterplots formed from a pair of variables. The variables are represented by the X-axis and Y-axis of each plotcell.  The observed values on the two varibles are represented by points in the little scatterplot. Each point  represents the values for (usually) one observation on two variables.

Normally distributed variables will have scatterplots which have the greatest density in the middle, are roughly eliptical in shape, and have no obvious outliers. 

The scatterplot matrix can be used as a control panel for selecting variables, pairs of variables and triples of variables. When you click on a plotcell, that pair of variables is selected. When you click on a diagonal cell, a single variable is selected. Shift-clicking will select more variables.

When you use the scatterplot matrix to select one, two or three variables, various changes will appear in other plots. The specific changes depend on the nature of the SpreadPlot. 
