"First, the concept is a great introduction for coaches, quarterbacks, and all players (as well as fans) to how to "stretch" or break down coverage. At core, the route involves four guys running "vertically" -- hence the name. They split the field four ways, and as a result typical "two-deep" (Cover two, Tampa Two) or one- or three-deep coverages (Cover three, Cover one man, certain zone blitzes) should not be able to defend the route."
http://smartfootball.blogspot.com/20...zalez.html?m=1