Polygon Mine Sweeper

A fun mine sweeper game - tap on a cell to reveal it - long tap on a cell to flag and un-flag it - tap on a revealed cell to automatically flag all hidden cells/reveal all hidden cells if it is obvious that the hidden cells are all flags/numbers - tap "undo" if fail - tap "new game" if want to start a new game - choose between "easy", "medium", and "hard" mode for difference grid size and number of mines