Yeah, multiple MRT members have contacted me to say this is a real struggle. If someone is on the move, it's virtually impossible to work out what direction they are going.
You would still get high densities of cells which share two words being present close together, leading to any issue with the third word causing a confusing location.
The word list already is 40k long. That's beyond most people's vocab and includes really awkward to spell words.
IMO, if the solution is to use words, then What4Words would have had a word list of less than 3000, resulting in a word list with less confusable words and more accessible to children and people who struggle to read or write.
Two reasons:
1. It needs to be reversible so you can go from words to lat/lon.
2. They wanted to use shorter words in cities, so the distribution of low n didn't want to cover the full range of m. (this could probably be solved by some sort of banding though).
I've added a section on padding oracle attacks towards the bottom.
I don't think there's a significant different in ease of understanding between most of the modes. I used CBC as it's one of the most common and familiar modes, and because it's where I have seen this issue many times. I don't see CTR used in the wild very often.
I also tend to use CBC for other demos as well, so it makes things consistent.
I considered using a padding oracle attack in the post, but it's aimed at a very basic level of understanding. I find padding oracles are much harder to describe to newcomers.
Also, the XOR malleability issue is present in lots of block modes of operation.
The odds are around 1 in 24 that you hit one of these squares in London.