def initialize_vml_shape
      pos = Axlsx::name_to_indices(ref)
      @vml_shape = VmlShape.new(:row => pos[1], :column => pos[0], :visible => @visible) do |vml|
        vml.left_column = vml.column
        vml.right_column = vml.column + 2 
        vml.top_row = vml.row
         vml.bottom_row = vml.row + 4
      end
    end
initialize the vml shape based on this comment's ref/position in the worksheet.
by default, all columns are 5 columns wide and 5 rows high