She left him with a single note,
Two lines in tear stained ink she wrote,
"I love you, but can't with you be,
Society would never agree."
Crumbling the note he threw away
Why should she heed what people say?
That lament haunted him day and night,
And he gave to despair and fright.
His search for her reached an impasse,
The lockless key a scrap of brass.
But he swore, his life he would spend,
Seek he would, till the world's end,
His journey was an endless one,
For a trace of her there was none.
 

And that was a Cyhydedd Fer couplet.

Who actually created this form is unclear as the Cyhydedd Fer couplet lends itself easily to the sonnet format. As the cyhydedd fer itself is an ancient form it is quite likely a series of 7 couplets was being used long before the advent of the sonnet.

However, the cyhydedd fer creates a different sonnet rhythm in the fact there is no meter requirement other than the rhyme every 8 syllables. The couplets allow the poet some flexibility in where to divide the poem with the pivot or volta which can be anywhere between lines 5 and 8 with the final couplet being a resolution.

The rhyme sceme is: a.a. b.b. c.c. d.d. e.e. f.f. g.g.

~Source: thepoetsgarret.com~