code: function() {
      var self = this;
      if (!this.get('screen')) {
        this.set('screen', new Screen());
      }
      this.updateTextLines();
      this.observe(this, 'change:text change:width', function() {
        self.updateTextLines();
      });
      this.observe(this, 'change:visible change:textLines change:height', function() {
        self.render();
      });
      this.render();
    }
docs: expect the attributes to have -----------------------------  * line and col (top left coordinates) * height and width