By learning how to climb out of her cot.
We predicted it two days ago that it would be days.
And it was today. After putting her back, upon discovering her wandering up and down the hallway with her little shopping trolley looking pleased with herself, and again, and again. We realised she was climbing out using her toybox as a springboard. HA, we thought, gotcha, and moved it far away from her.
DH went in to check on he just a second ago, to find her happily playing with some toys, nice and quietly in the middle of her room.
Oh dear.