i spent some time working on something like this - i wanted something that could carry as much information as a typical cryptographic hash, but be memorable to

i spent some time working on something like this - i wanted something that could carry as much information as a typical cryptographic hash, but be memorable to a human. it turns out that it's quite hard to make that much information memorable :o) (it's even harder to measure whether something is memorable, or even "different" - i ended up getting sidetracked into extreme value statistics, and then giving up) but one important trick was to make the pattern symmetric in some way, which seems to be also used here. although it halves the amount of data (assuming other parameters constant) it makes it much, much easier to remember. anyway, these look good (for this use case).