SUDOKU QUARTERLY of the first quarter of 2021 contains
the thirteen issues of SUDOKU WEEKLY of week 1 to week 13.
Each week, there is a Sudoku for each day.
All these Sudokus are magic:
From Monday (which has only one magic block)
until Saturday (with six magic blocks) each weekday has
one more magic block than the previous day.
On Sunday all blocks are magic.