Added 1977-02-18 11:37:26
App Freshness



Post Date:
2017-10-21 03:37:44

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This app contains an impossible version of the old 15 puzzle (that is, it starts in a mathematically-proved unsolvable mode). Make your friends try and re-try in the unsolvable mode, they will never succeed in solving the puzzle. When it’s your turn, press the invisible(hidden) button and you will be able to solve it easily.
It works like this:
– by pushing the “shuffle” button it starts in the unsolvable mode;
– by pushing at the same time the “shuffle” button and the invisible button on the left, it starts in the solvable mode. A small fly on the right top corner of the screen indicates that the normal mode is active.

Promo Video:


  • 15challenge Screenshot
  • 15challenge Screenshot

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  • Web Developer

    Oh, this application is a brilliant means to train my brains and to josh my friends! Thanks!

  • ciocky

    Very very nice! I have a won a beer with a friend…and got money back 🙂

  • balice

    Bought it and already had fun with my boyfriend: he tried hard to solve the puzzle, really hard. And was schocked to see me solve it in 32 seconds. Nice!!

  • zap

    Great idea! Really. I mean, to have fun with friends is perfect! And it is a nice implementation too. By far the best implementation of the 15puzzle on the store, not taking into account the plus of the impossible version. Good job.

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