Unstable Hilbert curve

Hilbert curves of even order cannot be overlapped with Hilbert curves of odd order (click the canvas to see it). This makes them somewhat problematic for Hilbert treemaps like the ones we showed in this and this examples.

According to our data cartography methodology, if a dataset is slightly changed, only a slight change should be reflected by the map. But, if we use Hilbert layouts, we can observe a disastrous change on an already full map if a single cell is added to it: the map will be flipped!

Peano curves are not affected by this problem (see here). A solution for fixing Hilbert curves is presented in this example.