Harry Kahne "Multiple Mentality Course"
This article makes remarkable claims for Kahne's "full brain" exercising course, included at the end.
Some of the exercises can be done in one's head, as it were, during the day's mindless tasks and would work with the thorough list of 3- and 4-letter words and codes etc. I offer in my new book MEMORY PALACE DEFINITIVE.
Would love to hear from anyone able to commit the hour or so a day to the course; it's a goal of mine when I have a little more spare time.