    class
    	WEL_COLOR_REF

    General
    	cluster: wel
    	description: "Color defined by intensity of the red, green, blue color."
    	create: make_by_color, make_rgb, make_system, make

    Ancestors
    	ANY
    	WEL_COLOR_CONSTANTS

    Queries
    	blue: INTEGER_32
    	green: INTEGER_32
    	item: INTEGER_32
    	red: INTEGER_32
    	valid_color_constant (c: INTEGER_32): BOOLEAN

    Commands
    	set_blue (a_blue: INTEGER_32)
    	set_color (color: INTEGER_32)
    	set_green (a_green: INTEGER_32)
    	set_red (a_red: INTEGER_32)
    	set_rgb (a_red, a_green, a_blue: INTEGER_32)

    Constraints
    	valid red inf
    	valid red sup
    	valid green inf
    	valid green sup
    	valid blue inf
    	valid blue sup