Mathematics, logic, and word game puzzles; a series of mathematics, logic, and word game puzzle books; syndicated columns dealing with mathematics, logic, and word game puzzles; magazine columns about mathematics, logic, and word game puzzles; syndicated magazine sections dealing with mathematics, logic, and word game puzzles; daily calendars featuring mathematics, logic, and word game puzzles; a series of books and written articles in the field of mathematics, logic, and word game puzzles; m...