def sample(str)
      @sample_x ||= 100
      @sample_y ||= 100
      rect x: 460, y: @sample_y - 40, width: 600,
           height: 180, fill_color: '#FFD655', stroke_color: 'black', radius: 15
      text str: str, x: 460, y: @sample_y - 40,
           width: 540, height: 180,
           valign: 'middle', align: 'center',
           font: 'Times New Roman,Serif 8'
      yield @sample_x, @sample_y
      @sample_y += 200
    end
def sample(str)
      @sample_x ||= 100
      @sample_y ||= 100
      rect x: 460, y: @sample_y - 40, width: 600,
           height: 180, fill_color: '#FFD655', stroke_color: 'black', radius: 15
      text str: str, x: 460, y: @sample_y - 40,
           width: 540, height: 180,
           valign: 'middle', align: 'center',
           font: 'Times New Roman,Serif 8'
      yield @sample_x, @sample_y
      @sample_y += 200
    end
Define a set of samples on some graph paper