list1 = ['little','blue','widget']
list2 = ['there','is','a','little','blue','cup','on','the','table']
list3 = set(list1)&set(list2) # we don't need to list3 to actually be a list
list4 = sorted(list3, key = lambda k : list1.index(k))
list1 = ['little','blue','widget']
list2 = ['there','is','a','little','blue','cup','on','the','table']
list3 = set(list1)&set(list2) # we don't need to list3 to actually be a list
list4 = sorted(list3, key = lambda k : list1.index(k))