6 bits
From LifeWiki
6 bits  
View static image  
Pattern type  Oscillator  

Oscillator type  Shuttle  
Number of cells  49  
Bounding box  40×26  
Period  75  
Mod  Unknown  
Heat  71.3  
Volatility  1.00  
Strict volatility  0.26  
Discovered by  Robert Wainwright  
Year of discovery  1984  
 
 

6 bits is the smallest known period 75 oscillator. It is a glider shuttle using three pentadecathlons as reflectors.