this is not necessarily about Hal, but since he was certainly closely involved with Satoshi
(if not with Satoshi Nakamoto Nakamoto, then at least with his close neighbour Dorian Satoshi Nakamoto)
I would like to put this out here about the double whitespace riddle:
https://vimhelp.org/options.txt.html#%27joinspaces%27 'joinspaces' 'js' 'nojoinspaces' 'nojs'
'joinspaces' 'js' boolean (default on)
global
Insert two spaces after a '.', '?' and '!' with a join command.
When 'cpoptions' includes the 'j' flag, only do this after a '.'.
Otherwise only one space is inserted.
NOTE: This option is set when 'compatible' is set.
Could this be the explanation for this quirk in Satoshis writings?