Pass the Pair

You’ll be given a starting pair of letters and a list of words. At each step:

1. Insert the pair somewhere inside the next word — as a contiguous chunk — so that the result is a new word.
2. Pull out a different two-letter slice of that new word, such that what remains is also a word.
3. The slice you pulled out is the pair you insert into the next word. Repeat.

So every word you build splits two ways: undo the insertion and you get the word you started from; make the other cut and you get a word you throw away.

A quick example of one step: given RI and CARED –> CAR·RI·ED. Then, you could remove the AR out of CARRIED and you’re left with CRIED. Note that you couldn’t remove the IE slice out of CARRIED, because CARRD is not a word, nor could you remove the RI because the new two-letter slice must be different.

The puzzle

Start with: AL

1. SEED
2. BRING
3. POLE
4. BANS
5. TIGHT