@Koen
When it comes to Voynichese, I (currently) do not think that spatial spread is the only mechanism that is employed there, but I suspect that it may be part of the play - just because of all those strange effects like multipass, p's affinity to the paragraph-starting line, the somewhat "fuzzy" ordering of first letters of lines etc.
The notable property of spatial spread is that it reduces the average word-length, and then if it is combined with something that increases it (like e.g. a verbose cipher), then the perceived word length will be normalized. If both processes decrease H2, then H2 will be exceedingly low.
It is a very good comment of yours about the intra-bigram positional rigidity, in fact there is a very simple mechanism which would produce a similar effect, and this is what I am currently looking into
When it comes to Voynichese, I (currently) do not think that spatial spread is the only mechanism that is employed there, but I suspect that it may be part of the play - just because of all those strange effects like multipass, p's affinity to the paragraph-starting line, the somewhat "fuzzy" ordering of first letters of lines etc.
The notable property of spatial spread is that it reduces the average word-length, and then if it is combined with something that increases it (like e.g. a verbose cipher), then the perceived word length will be normalized. If both processes decrease H2, then H2 will be exceedingly low.
It is a very good comment of yours about the intra-bigram positional rigidity, in fact there is a very simple mechanism which would produce a similar effect, and this is what I am currently looking into

