There's a book called "Simplexity" also a theory by that same name, that states things that are seemingly simple are made very complex, ie. the cell phone and the 65 page user's manual...and complex things are somewhat simple, as in crowd control. There are columns and obstacles at exits, by elevators, and such locations for a number of reasons. One of which is that the few seconds it may take the crowd to move around the obstalce also helps move the crowd which has already moved past the obstacle. The crowd behind is slowed by the obstacle, thereby reducing the chances of too many people occupying too little room. Very fascinating read.
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seeking to balance risk and reward
Audaces fortuna iuvat...fortune favors the bold
Practice methodical caution...Les Stroud