Algorithm Brainstorming.

A poem is:

A collection of words all of which are in collision with each other.

When a word is moved:

If it belonged to the poem, we must decide if it has left the poem.

If it does not belong to the poem, we must decide if it has joined the poem.

When the last two words of a poem are pulled apart

We must see if where the last word to be moved landed starts a new poem

Seems simple enough. Annoying that it's nonetheless broken.

It probably needs unit testing.