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This is copy paste of http://0hh1.com http://0hh1.com

• mhei 9y ago
  Or possibly the other way round? 0hh1.com was registered in 2014 according to whois info, the puzzles on this site go back to 2011. (I'm not claiming this is proof, of course)
  • rplnt 9y ago
    Also, the list of puzzles on the site goes to March 2011. I think this is a nice case of taking something interesting and making it more approachable, perhaps even fun.
  • kmm 9y ago
    They're older than that, this kind of puzzle is called a Takuzu or Binairo and was invented in 2009 by a pair of Belgians: https://fr.wikipedia.org/wiki/Takuzu https://fr.wikipedia.org/wiki/Takuzu