Monkey had some free play with the cuisenaire rods, and next thing I know, he's building a nativity scene. This is one of the first times that he's built pictures with the rods. The yellow and green is the manger, Baby Jesus is purple, and Mary and Joseph are the pink rods. The blue ones are "a force-field that protects the stable from all bad guys."
He built several incarnations of his stable, with different size rods. I thought it was interesting to see how he dealt with the shrinking size of the building - eventually, Mary and Joseph were squeezed right out of the Stable and had to be outside.
It is always interesting to watch what he does when he have free play with the rods. I wouldn't have guessed that something like building rod pictures would be very "mathy" but in watching him build the various versions I realized that he was learning, very naturally, about the difference it makes to use larger or smaller building materials: when he shrank the walls, the interior shrank too, and thus the difficulties that Mary and Joseph were facing in being inside. This knowledge should come in handy when we start looking at perimiter and area. In the mean time, he had a good time, and that is valuable in and of itself - especially when doing math!