I was wondering if how I could switch logic level MOSFETS with CharliePlexing. Would I simply make use of regular diodes connected to the gate?

Also I have read the tutorials but I am having a brain freeze as to the pattern of the array. Most of the examples stop at 6 LEDs. How would I do a 12 LED array? What is the pattern?

 

OK I gave the 12 LED thing some thought and I guess it is something like this?