"Luck is what happens when preparation meets opportunity." - Darrell Royal
Question #89749 posted on 05/23/2017 1:22 a.m.

Dear Frère Rubik,

Which people should go through which doors when entering/exiting the library in order to maximize efficiency?

– Larry Wayne


Dear Larry Wayne,

Well, who'da thunk it? Someone actually read my bio page!

For this question, we'll look at the ground floor of the library. Specifically, we'll look at the southwestern-most doors, since they're the ones I use the most to go from the library to the ESC when I'm going to class and therefore are the doors at which I experience most of my frustrations:


Now, when large groups of people walk down this hallway, they tend to move to the right hand side, creating two lanes of traffic, like so:


Why do we do this? It could be because we tend to drive on the right side of the road and so subconsciously we do the same thing when we're on foot. I found some articles about why different countries drive on the right side or the left, and this discussion about why people walk on the side of the sidewalk they do. It's interesting, but far from conclusive.

But anyway: in this situation, walking on the right side of the hall, which door should you exit out of? Would either of them be equally efficient? Let's take a look.

If the people exiting/entering the building choose the door that is on their right, the traffic flows like this:

good way.png

As you can see, this makes both the people in the blue lane and the people in the red lane happy, since they're all able to enter/exit the building in a smooth, continuous path without any interruptions. Sure, they show their happiness in different ways, but at the end of the day, what does it matter? Just because the blue people have their eyes and mouth wide open does not mean that we should give in to the temptation to label the red people as merely "content." Surely we can agree that, just as there are billions of people on this earth, there are also billions of ways to express our happiness.

Now, what would it look like if they tried the other door?

bad way.png

Now, we find that things have changed. The red people people are still happy; entering through the left door has done nothing to interrupt their walking path or their sense of inner contentment. The blue people, though, find themselves at a loss as to what they should do. While the steady stream of red people cuts them off from the door on the left, there are too many red people coming in the door on the right for the blues to exit there, either. They resign themselves to wait, hoping this interruption will turn out to be a minor one.


It isn't meant to be. The red people continue streaming in through the left door, blissfully unaware of the problem they're creating for the blues. And how could they be? They're busy people leading busy lives, and they've been caught up in the temporary euphoria of uninterrupted traffic flow. They see themselves; in some instances, they may also see their fellow reds and bask in the joy of communal movement towards a common goal. It is highly unlikely that they see the blues.

The blues' confusion has turned into frustration. Will there be no end to the line of reds streaming through the right door? Some may make an attempt to break through the line to the left door, but the reds unwittingly have created an impenetrable barrier with their joyful movement. The blues' frustration turns into desperation, and in some cases, anger. They didn't do anything to deserve this! In fact, they get angry at the fact that they're angry. This miserable mood isn't their fault at all! Why should they have to get frustrated and upset because of the ignorant mistakes of others? Confound it all, it's not fair, do you hear me? It's not fair!

And yet the reds continue to flow.


Eventually, the blues' anger reaches its boiling point. Future historians looking on the actions of this day will be filled with a sense of tragic pity. They, so far removed in time, can clearly see how this cause led to that effect and how the whole thing might have been avoided. If some people had perhaps been more thoughtful, and others had committed themselves beforehand to never do what would ultimately be done, then perhaps this day could have slipped unobtrusively in line with its fellows, completely normal and unremarkable. Sadly, this is not the case.

Pushed to the breaking point by their frustration and desperation to reach class on time, the blues will eventually move en masse, scattering like so many ball bearings from a discharged shotgun shell. Their random motion cuts off the red line, surprising them out of their felicitous reprieve. For a few agonizing moments, no one enters or exits the library at all. Slowly, the blues regain their sense of composure and make their way towards the doors. If some insightful red acts quickly enough, she will boldly direct her line toward the door on their right, allowing the blues a dignified exit through the other door and restoring a sense of order and balance to that small section of campus. Or, perhaps, too stunned to learn from past mistakes, she will remain in front of the door to her left. The blues, with no other option, will go through the other door, and the fortunes of red and blue will have been effectively reversed. Those blues at the front of the line will remember the tragedy and seek to warn those that come after them, but invariably the blues at the end of the line will not have paid attention and will fall into the same locomotive bliss as their red counterparts from before. The reds will wait outside, tensions building until the horrible cycle of events repeats itself once more, causing all those involved to lament the futility of time and history.


But there is a way to break this chain of sorrow. You can be the difference. You can be the change you want to see in the world. You can help everyone experience the joy of uninterrupted movement through open doors.

You can choose the right.

-Frère Rubik