Period20 glider gun
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Period20 glider gun  
View static image  
Pattern type  Gun  

Number of cells  672  
Bounding box  78×42  
Period  20  
Barrels  1  
Discovered by  Matthias Merzenich Noam Elkies  
Year of discovery  2013  

Period20 glider gun is a true period20 glider gun that was discovered by Matthias Merzenich in 2013 and improved by Karel Suhajda^{[1]}, based on Elkies' true period 24 gun. This is the shortestperiod trueperiod gun known so far.
Filtering the output of the gun with a blocker yields the smallest known period40 glider gun, beating the eponymous period40 glider gun at its own game. The further addition of Rich's p16 doubles the period again, resulting in the smallest known period80 gun, and adding 68P32.1 on top of that doubles the period once more to 160.