An expression which evaluates to a list of 1 or 2 numbers, the x-axis scale and y-axis scale, or the uniform scale when only a single value is given.
Example
// Create a new pattern paint from an image filevariable tPatternputpatternwithimagefromfile"images/pattern.png"into tPattern// Scale the pattern to twice the current widthscale tPattern by [2,1]