I have a habit, when a concept isn't working for me, to repeatedly access it in different ways, so that eventually my brain might get the picture and respond reliably.  That isn't always working that well for me any more, but it is just something that I am so familiar with.

When engaging this, I get confused when i think of the stats concept of "combinations".  i'm not sure they're relevant here, but I can barely understand what they are.  I think I