Beautiful structure

Nicely Penned, Wonderful Job!!!

Grey,
the
color
of your smile,

^^I like how you have used the words "grey smile". It really sets the tone and tells the reader that happiness is out of reach. The association of a dull color to a smile is enough to express sadness.

unborn promises

^^Here is another beautiful line. Its like promises have been thought about but unable to be delivered/or unable to go through with it due to circumstances...touching.

This form sounds interesting and you have penned it delicately without it loosing its meaning, depth or sadness. With the given number of words, you have managed to touch the reader with this unknown sadness...beautifully done.

I am not familiar with this form, so it's neat to come across it and become educated about it.

Plus, the word "lament" is one of my favorite words to use - love how much it conveys in two syllables and the way it sounds.

Simple yet powerful image about grey being the color of someone's smile. Usually, when I see someone smile, I look at it in two ways. One, they are smiling only with their lips or two, they are smiling with their teeth and are openly, fully conveying that happiness. But for a smile to have a color is a truly thought-provoking idea.

I am not sure about the last line, this is strictly my opinion but I feel that "on the departure's porch" sounds a bit awkward. I don't think "the" is needed. I like the ending image of this porch, maybe where this love was born and it does remind me of departing or visiting home again, but not sure "departure" was the best to use?