This is a Hilbert curve implementation in Haskell.
A Hilbert curve (also known as a Hilbert space-filling curve) is a continuous fractal space-filling curve, which is a curve whose range contains the entire 2-dimensional unit square.
To run the test suite, execute the following command:
stack setup && stack testghci> :l src/HilbertCurve.hs
[1 of 1] Compiling HilbertCurve ( src/HilbertCurve.hs, interpreted )
Ok, modules loaded: HilbertCurve.
ghci> xy2d 2 1 1
Just 2
ghci> d2xy 2 2
Just (1,1)