It turns out she is pretending the acorns are birds- and the acorn caps are bird nests. Big acorns are the mommy&daddy birds, little acorns are baby birds. Some acorns are eggs. It seems to be arbitrarily decided.
I think this is a hilarious, creative, and super fun idea.
The birds love to fly around our apartment and I've seen a few in places I'm not particularly fond of (the refrigerator: "it's an egg, mama!") but it is harmless and she's having a great time so I can't complain.
What creative uses have you heard of for acorns?