The Select Pattern window lets you select a pattern to be associated with the current keyword.
As you make changes to this pattern's density, colors, and/or line width, these will also be reflected in the preview box.
Tip: If you need to plot a particular lithology as a solid color with no pattern, simply choose a blank pattern block for that keyword (scrolling down to find one), and set the pattern's background color to the desired color for the lithology type.
Back to the Select Pattern Window