Toward Definitions: 10th Approximation

This is the tenth and last of a series of approximations, posted with the intention of moving gradually closer to, without ever hoping to arrive at, a definition of the formal aspects of haiku. Although these have been presented in a tone of pedantry only to be expected, I fear, from a retired academic, they are meant essentially to outline my personal understanding of what I think I'm doing when I write what I claim is haiku. Thoughts on issues of content, including the haiku/senryu relationship will be presented now and then in no particular order. Like the haiku and senryu I've posted, these approximations invite comments, questions, corrections, and criticism.
All of these approximations have assumed as the norm the three-line form most familiar in English. Is that the form of haiku? Well, no. There are also one-line, two-line, and four-line haiku. This raises a question [Excuse a cranky old English teacher's observation that it doesn't beg the question; it raises it.]: How much formal variation can be allowed to haiku before it ceases to be haiku and becomes simply the short poem? The answer is simply stated: There is no answer.
My interest in my own practice has been primarily in the three-line form, and I expect that will continue to be the case. I post here one of my few experiments in the two-line option. I wrote this one in February.

overcoats flapping

midwinter thaw