You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: color_the_circles.rb
    path of file: ./repos/glimmer-dsl-libui/examples
    
    the code of the file until where you have to start completion: require 'glimmer-dsl-libui'

class ColorTheCircles
  include Glimmer
  
  WINDOW_WIDTH = 800
  WINDOW_HEIGHT = 600
  SHAPE_MIN_SIZE = 15
  SHAPE_MAX_SIZE = 75
  MARGIN_WIDTH = 55
  MARGIN_HEIGHT = 155
  TIME_MAX_EASY = 4
  TIME_MAX_MEDIUM = 3
  TIME_MAX_HARD = 2
  TIME_MAX_INSANE = 1
  
  attr_accessor :score
  
  def initialize
    @circles_data = []
    @score = 0
    @time_max = TIME
    
  def add_circle
    circle_x = rand * (WINDOW_WIDTH - MARGIN_WIDTH - SHAPE_MAX_SIZE) + SHAPE_MAX_SIZE
    circle_y = rand * (WINDOW_HEIGHT - MARGIN_HEIGHT - SHAPE_MAX_SIZE) + SHAPE_MAX_SIZE
    circle_size = rand * (SHAPE_MAX_SIZE - SHAPE_MIN_SIZE) + SHAPE_MIN_SIZE
    stroke_color = Glimmer::LibUI.x11_colors.sample
    @circles_data << {
      args: [circle_x, circle_y, circle_size],
      fill: nil,
      stroke: stroke_color
    }
    @area.queue_redraw_all
    self.score -= 1 # notifies score observers automatically of change
  end