If you are not familiar with them, let me give you an example. If you Give A Pig a Pancake, they will want syrup. The syrup will make them sticky and they will want a bath. In the bath they will want a rubber ducky....etc. So it goes on and on. Pretty much like the way MY brain works. My real life example: I have people coming over and need to clean the bathroom. In the bathroom I clean the pee on the floor (I have boys) and I see dirty baseboards, so I get out the paint....See, I guess the author's characters have ADD like the ADD I get when cleaning. :)
Anyway, I pulled out these books and began creating a unit for one. Then that meant I created a unit for another one. Oh, the vicious cycle!!