Koch fractal snowflakes are built on an equilateral triangle, with equilateral triangles on the side. https://www.thingiverse.com/thing:3486462 creates these.
A variant which works better as tiles is to use a square base with right angled triangles on the side. Unlike the snowflake curve, the curve produced by mirroring the sides - the anti-curve- is simple and curve and anti-curve (of the same order) together tessellate (as the snowflake curves do).
This script creates a tile with parameterised outer and inner boundaries, and an optional base for a container. The difference between inner and outer can be either scaled or inset by a fixed thickness. A fixed thickness often looks better for small values but breaks down at higher values when scaling is better. Scaling preserves the shape, insetting does not.
A pair of matching containers would look good.
Customiser seems a bit reluctant to display - a general problem?
More on this in my blog http://kitwallace.tumblr.com/post/183403292674/another-koch-fractal-tiling