BlinkerSpawn wrote:13 gliders: ... Unfortunately not an improvement.
This can be reduced to 12 by building the still-lifes simultaneously. This could previously be done from 11 gliders (my web page currently says 12, but most blocker-based oscillators were improved by 1 by Bob Shemyakin's 5-glider blocker synthesis from no later than 2015):
x = 180, y = 77, rule = B3/S23