public static IZ1BrushSequence DualBrushes(Color positiveColor, Color negativeColor, int steps)
{
return new Z1BrushSequence(
positiveBrushes: positiveColor.FadingSpread(steps + 1).ToBrushes(),
negativeBrushes: negativeColor.FadingSpread(steps + 1).ToBrushes()
);
}