Procedurally generated watercolour textures

While working on my Honours Project I discovered the wonders of procedural generation, and here I had another go at it with procedural watercolour textures. I found a couple of ways to do it: one is from Tyler Hobbs, in which a shape is deformed multiple times, and the other is from this Reddit post. I tried the latter: the algorithm recursively expands a small image (here 3 × 3 pixels) by adding a new pixel between the existing ones, and their colour is chosen through a linear interpolation between the neighbouring ones.

The implementation is in Processing (Java — ew).