A scrim set has a single, two doubles, a half single and a half double in it.* The Gaffer says to put in another single into the tweenie that you're standing next too. The problem is that it's already got a double and a single in it, leaving you without anymore singles in the scrim bag for that light. The Gaffer also tells you to pull out a single from the redhead when you're done with the tweenie. But the redhead doesn't have any singles in it. Just the two doubles.
What do you do?
(Bonus question: What do you have when you've got two doubles and a single in a light?
Answer: The wrong light.)