SUDOKU HARD - HARD SUDOKU CAN BE FUN FOR ANYONE

Quads are much rarer, and they’re significantly less handy in a method because they don’t Allow you to slim down a large number of candidates abruptly, but when you spot one, it’s well worth investigating. Solving single squares also can change quads into triples or pairs, so don’t ignore these!Both of those medium and hard level sudoku puz