FERMAT - Challenge your limits of memory! Brain training game app

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FERMAT - Challenge your limits of memory! Brain training game app' is the full title of this memory boosting game. 


The objective is simple: memorize where all the number are.  Then, when you're ready, the tiles are all turned over and you must identify where they are.


I'm on level 10 which has 14 numbers in a 4x4 grid.
https://itunes.apple.com/app/id1070977437?mt=8