select an el which appears a few times in a row

select an el which appears a few times in a row

 a=['a','b','b','h','h','a']
 puts a.select{|l| a.count(l)>1}.uniq
 puts "--sec time in a row:--"
 a.each_with_index do |item,index|
    if item==a[index+1]
      puts item
    end
 end