Your kid is now trying to understand the concept of space. With her exploratory nature she would be trying out different experiments at her own level. She is keen to know if she can fit her body in the cupboard or her head in a bucket. She would be trying out all different kinds of things to help in her spatial understanding.
What you need to know
As she is in an exploratory mode so she might also find herself in dangerous situations when she is trying out a new spatial experiment. It is important to make sure that you are around to warn her or help her out from any such situation. Shape puzzles and jigsaw puzzles also help in understanding this concept better.