Dominic system (after Dominic O'Brien is a Person-Action image association system for numbers in specific order. Uses it to turn two digit numbers into famous people. Also associates an action with a famous person, representing the same two digit number. Now you can imagine a 4 digit number as a person doing an action A mobile number would be 2 person action combinations in sequence. The upfront work is remembering the persons and actions as images for each of the 00-99 two digit numbers. Then putting a four digit number together requires putting them in sequence e.g. in a one of your preselected [[Memory palaces 20201007192310]], The act of remembering is constructing the images and placing them in the memory palace of choice.

There is also a Person-Action-Object system PAO, which allows you to do three pairs of digits in one image. Allowing 1 million numbers to remember.