This trio come as a set. Three notebooks representing three different states: solid, liquid, gas. Liquids and gases can flow. Solids keep their shape. Gases can be squashed. Water can be all three: liquid, ice, steam
We marbled many pages to get the design for the liquid state, and then opted for a half tone gradient fill for gas and a molecular representation for the solid book.
The notebooks have recycled interior pages: liquid = ruled, gas = dotted and solid = plain, and are a perfectly pocket-sized (A6).