Antifreeze. Still no particular progress to report on the 2^N metacell -- it probably needs a full day of concentration to finish, and I haven't had that to spare for a while.

-- Or else there were other things that needed doing more urgently. All kinds of exciting things have been going on in Conway's Life lately, like new "minstrel" tagalongs for (2,1)c/6 knightships, and the addition of labeling functionality to LifeViewer, which makes pattern documentation *way* easier:
http://conwaylife.com/forums/viewtopic.php?p=67897#p67897