1class ButtonBuilder
 2  def initialize(name)
 3    @button = Button.new(name)
 4  end
 5  def centered(coordinates)
 6    @button.control.center = coordinates
 7    self
 8  end
 9  def when_clicked(command)
10    @button.bind_to(command)
11    self
12  end
13  def build
14    @button
15  end
16end