In the past couple of months I have been experimenting with various ways to use the numbered memory palace (every location is connected to a 2 digit number/single playing card using the New memory system for fast translation of numbers) and I have felt an increasing awareness of a relative problem of all of my variations; they lack the integration advantage of the person/object/action type methods.
So all of a sudden I got this eureka moment in which I got an interesting idea.
What I came up with is basically this: 4 or 5 2 digit/1 card categories, namely (location), person, object, animal and food.
I am not fully conviced that using the location as an element is the best way to go; doing this requires some way to keep track of the order of locations used (However it does have have the magical consequence that you only need 10 locations for a 100 digit number). But I am rather convinced that having numbered locations is very useful with the learning of the other elements of the system; both the persons and the animals can be easily connected to the locations and thus also to the 2 digit numbers/playing cards and the objects are easily connected to the persons as the food items are to the animals.
example of 4 category variation:
52/4 = 13, so I need 13 locations (I can choose the best 13 locations sequence of my 100 locations memory palace) for a deck of cards. In each location I imagine basically 2 pairs; 1st pair is the person with object and the 2nd pair is the animal with food item.
real example from my system (I have all the elements complete): 31 36 60 18 (pronounced as mi mab bo if) is Chuck Norris on a motorcycle and a rabbit drinking a can of red bull.