def self.constants
@constants ||= Set.new %w(
indigo gold firebrick indianred yellow darkolivegreen
darkseagreen mediumvioletred mediumorchid chartreuse
mediumslateblue black springgreen crimson lightsalmon brown
turquoise olivedrab cyan silver skyblue gray darkturquoise
goldenrod darkgreen darkviolet darkgray lightpink teal
darkmagenta lightgoldenrodyellow lavender yellowgreen thistle
violet navy orchid blue ghostwhite honeydew cornflowerblue
darkblue darkkhaki mediumpurple cornsilk red bisque slategray
darkcyan khaki wheat deepskyblue darkred steelblue aliceblue
gainsboro mediumturquoise floralwhite coral purple lightgrey
lightcyan darksalmon beige azure lightsteelblue oldlace
greenyellow royalblue lightseagreen mistyrose sienna lightcoral
orangered navajowhite lime palegreen burlywood seashell
mediumspringgreen fuchsia papayawhip blanchedalmond peru
aquamarine white darkslategray ivory dodgerblue lemonchiffon
chocolate orange forestgreen slateblue olive mintcream
antiquewhite darkorange cadetblue moccasin limegreen saddlebrown
darkslateblue lightskyblue deeppink plum aqua darkgoldenrod
maroon sandybrown magenta tan rosybrown pink lightblue
palevioletred mediumseagreen dimgray powderblue seagreen snow
mediumblue midnightblue paleturquoise palegoldenrod whitesmoke
darkorchid salmon lightslategray lawngreen lightgreen tomato
hotpink lightyellow lavenderblush linen mediumaquamarine green
blueviolet peachpuff
)
end