Drag and Drop: Wrong if the state is ...

Hey, I've combed through some discussions and can't seem to find an answer yet.

I'm wanting my learner to organize a cash drawer using the free form drag and drop. I have a few bills upside down, if the learner clicks on them they will flip over. What I can't figure out is a way for them to get it wrong when the state of the currency is "back". I don't want to get too far into the design of this if it simply won't work.

I've attached the slide. 

Anyone know if I can accomplish this?