This is an invented form (Aren’t they all), created by a Canadian Poet named D. D. Michaels who writes on Allpoetry.com, with many aliases over the 2-1/2 years I have followed him.
The Ababette is:
A 24 line poem,
Stanzaic, consisting of four sestets
Rhyme pattern: abcbc abdabd abeabe abfabf
Metrical, with all “a” lines being iambic dimeter
and all others being iambic trimeter.
See Picture HERE