Hello there. I need some help with fluidity/hydroventure.

I have problems getting a puzzle piece and a rainbow flower in the left side of chapter one. For your reference: It's the second square from the top left corner on the picture above. (The narrow one.)
It looks like if you need to be an ice-block to break the wooden barrier and enter the small passage. But I can only get into this area as water. And there is no form changer, not even in the field below (with the bath tub and the rubber ducks).
Has anyone found out how to get these two items? I have all abilities even the squirt from chapter 4 but still can't figure out how this works.


