class Point(
  var x:Double = 0.0,
  var y:Double = 0.0
  ) {
  override def toString = "[" + x + ", " + y + "]"
}

import java.awt.Color
class Pixel(
  xp:Double =0.0,
  yp:Double =0.0,
  var color:Color = Color.BLACK
  ) extends Point(xp, yp) {
  override def toString = super.toString + " " + color
}