Events
When both 
W+
and 
W- 
decay to produce a quark and an antiquark we get
events containing two quarks and two antiquarks.
We therefore expect to see four "jets" of hadrons:
 
Example
Event No. 1
End-On View of Event
 
 | 
Side View of Event
 
 | 
Side View of Event with Cones Drawn to Show 4 Jets
 
 | 
 
Example
Event No. 2
End-On View of Event
 
 | 
Side View of Event
 
 |