A 2D algorithm that combines Peano (3x3) and Hilbert (2x2) blocks was published by Lutz Tautenhahn in 2003
A 2D algorithm that combines Peano (3x3) and Hilbert (2x2) blocks was published by Lutz Tautenhahn in 2003:
[1] Lutz Tautenhahn: Draw a Space-Filling Curve of Arbitrary Size, http://lutanho.net/pic2html/draw_sfc.html, 2003.