def translate(x, y, z)
      @coordinates.each do |c|
        c.translate(x, y, z)
      end
    end
def translate(x, y, z)
      @coordinates.each do |c|
        c.translate(x, y, z)
      end
    end
Moves the coordinates of this contour according to the given offset
 vector.

 @param [Float] x the offset along the x axis (in units of mm)
 @param [Float] y the offset along the y axis (in units of mm)
 @param [Float] z the offset along the z axis (in units of mm)