Egg Carton Craziness

It's funny to me that despite my attempts to plan fun new things for Erik, so many of the things I post here are the result of desperation. Things like letting Erik help with housework or cook with me are really just desperate attempts to get him out from under foot and occupied while I do whatever I need to do (luckily these activities also really good for him).
Today's activity is no different. I was trying to cook dinner and Erik was hanging on me crying and begging for some attention. I had just used the last egg in my egg carton and hoping to get him off my back for a moment I handed it to him. Then, I realized that we could make this into something much more fun with almost no extra effort on my part. I took him and the egg carton over to the toy box and we dug through until we'd found a whole pile of toys that were little enough to fit inside. I showed him how to put them in and open/close the lid and he was hooked. It was awesome! The next morning, I pulled out some pom poms I had lying around and gave him those to put in the carton. He loved it!
This activity has great learning potential. In addition to working on the vocabulary words "open" and "closed", he also practiced hand-eye coordination and fine motor skills as he dumped the toys out and put them back in. He played with that egg carton for several days until he'd completely destroyed it, and then we had to throw it away. By the time I have another one empty for him it'll be like a whole new adventure again.

Where did they go?