A Hilbert curve is a space-filling (snakey) curve through a 2D space:
Image of 8 by 8 Hilbert curve
This can be very useful for mapping a 1D value, into a 2D space. For example, it is commonly used to map IP addresses into a 2D space.
I recently created a library for Go that can map to and from a curve. The project is hosted on Github, and can be used like so:
import "github.com/google/hilbert"
// Create a Hilbert curve for mapping to and from a 16 by 16 space.
s, err := hilbert.New(16)
// Now map one dimension numbers in the range [0, N*N-1], to an x,y
// coordinate on the curve where both x and y are in the range [0, N-1].
x, y, err := s.Map(t)
// Also map back from (x,y) to t.
t, err := s.MapInverse(x, y)
The project contains some demos, such as this cool animations:
