function mark_weekends()
% mark_weekends puts vlines were the weekends are

     vline(30, 'r--', '1st Weekend Start')
     vline(30+60, 'r--', '1st Weekend Finish')
      vline(30+60+108, 'k--', '2nd Weekend Start')
      vline(30+(2*60)+108, 'k--', '2nd Weekend Finish')
      vline(30+(2*60)+(2*108), 'b--', '3rd Weekend Start')
      vline(30+(3*60)+(2*108), 'b--', '3rd Weekend Finish')
       vline(30+(3*60)+(3*108), 'r--', '4th Weekend Start')
       vline(30+(4*60)+(3*108), 'r--', '4th Weekend Finish')
        vline(30+(4*60)+(4*108), 'k--', '5th Weekend Start')
        vline(30+(5*60)+(4*108), 'k--', '5th Weekend Finish')
         vline(30+(5*60)+(5*108), 'b--', '6th Weekend Start')
         vline(30+(6*60)+(5*108), 'b--', '6th Weekend Finish')
          vline(30+(6*60)+(6*108), 'r--', '7th Weekend Start')
          vline(30+(7*60)+(6*108), 'r--', '7th Weekend Finish')
            vline(30+(7*60)+(7*108), 'k--', '8th Weekend Start')
            vline(30+(8*60)+(7*108), 'k--', '8th Weekend Finish')
            vline(30+(8*60)+(8*108), 'b--', '9th Weekend Start')
            vline(30+(9*60)+(8*108), 'b--', '9th Weekend Finish')
            vline(30+(9*60)+(9*108), 'r--', '10th Weekend Start')
            vline(30+(10*60)+(9*108), 'r--', '10th Weekend Finish')
            vline(30+(10*60)+(10*108), 'k--', '11th Weekend Start')
            vline(30+(11*60)+(10*108), 'k--', '11th Weekend Finish')
end

