Fair question Duncan and you are not the first to ask it.
I had started on the design some 12 months ago long before I saw the Makaira video. At that stage I had a hexagon shape linked by lugs exactly as they had - pure coincidence. The holes in mine were still being calculated at the time to allow the correct airflow through the pot, so I saw their design as inferior and allowing far too much air flow to be much use, which it still is by the looks of it.
Mine also had versatility with the moving grill arrangement already in place, so the multi use of mine is far superior to their set up. Plus use of different materials and slicker design, different measurements and application.
Ultimately, at first glance I can be accused of copying the design, based purely on the side lugs and a hexagonal shape alone, and that's it! After that there's nothing similar about the two stoves, so I very much doubt I will be getting any calls from the legal people ;-))
Put it this way, if I had designed the stove as a circle, or a square, what other stoves would it be compared to? There are loads around the world if you look hard enough, and I have been looking very hard for the last year to see what home made designs people have tried.
I hope that answers your question. Not offended by you asking it, as far as I'm concerned 20% coincidence and 80% brilliance!