Download or read book Puzzles for Brain - Mega Sudoku 400 Hard to Expert Puzzles written by Alexander Rodriguez and published by Independently Published. This book was released on 2019-06-12 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: The puzzle a 16 x 16 grid made up of 4 x 4 subgrids (called "regions"). Some cells already contain numbers, known as "givens". The goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1 through 16 exactly once. Each number in the solution therefore occurs only once in each of three "directions", hence the "single numbers" implied by the puzzle's name.