We got the little angel this new bath toy.  One part of it attaches to the side of the tub.  You pour water in the top with the included, matching cup, and a little waterwheel turns.  We weren't sure if the little angel would be into it or not, but I was almost as fascinated by it as I was her crib-side aquarium thingie with the real water noises. 

We showed her how to do it a few times, and all of the sudden she was dumping water on the octopus (he being the axis of the waterwheel) and laughing with glee.  Now, this isn't advanced behavior for a fifteen-month-old child, but it IS something she'd never done before.  She also recently figured out how to put her puzzles together correctly.  When we first gave them to her, she would just stare at them blankly, not even sure how to pick up a piece with the knobs the size of her nose.

All of this rapid advancement is shocking to me.   It seems sort of ridiculous that she can go from not being able to walk to hydrotherapy in one month.