OK, OK! I confess! Actually it started when John was writing a haiku, but it was too much to be a haiku, so he decided to change it to a tanka. That wasn't working out, so he decided to try something new. He showed it to me and said that it was a mookuka. He pointed out the meter and rhyme scheme and said, "Try THAT, smartypants!"
I decided that I liked the style, so here we are. A new form.