Each themes returns an array of RGB values [R, G, B] for the provided color index.

Fire:	The default theme. Themes::Fire produces bright fiery fractals.
Water:	Deep blues and greens.
Winter:	Lots of blue. Looks best with set_color = [255, 255, 255].
None:	Coordinates outside the fractal set will appear white in color.

Example:

mandelbrot = Mandelbrot.new
mandelbrot.theme = Themes::Winter