As I said, it hardly matters whether Doublewide Chess has been previously
published under some other name.
The importaint thing is that Doublewide has remarkably interesting
strategical implications which need to be discussed in full before anybody
can speak of Triplewide or Infinitewide Chess.
The advantage of being a fairly strong chessplayer (I'm an FM, which
sounds great to you but which means zilch when I play chess) as well as a
well-eductaed variant inventor is that I can understand perhaps on a good
day I can dig more deeply into a variant which catches my attention.
Doublewide is an important building block. After I started writing about
it, I discovered there was more that needed to be written.
Maybe in a few days....