I have a list of strings, and I want to pair them in such a way that the last and second last is one pair, second last and third last in one pair and so on with a three dots in between.

### Example:

Let's say I have the following list

```
['a', 'b', 'c', 'd', 'e']

```

and I want to convert this into something like this

```
['e...d', 'd...c', 'c...b', 'b...a', 'a...none']

```

So far I have done the following,

```
>>> import string
>>>
>>> letters = string.ascii_lowercase[:5]
>>> letters = iter(reversed(letters))
>>> pair_iter = (c + '...' + next(letters, 'none') for c in letters)
>>> pair_iter = list(pair_iter)
>>> pair_iter
['e...d', 'c...b', 'a...none']

```

I am not sure what else to do in this case, I do know that `next` go to the next string, but how should I copy the previous one and then go to the next one?