For the last couple of months, the most popular article on Frankly Curious is, This Is Not a Math Joke. I assume it is being passed around on reddit or something. I really have no idea if people like it because they agree with it or because they find it amusing that people like me exist. It is about a “math” joke that appeared on an episode of The Simpsons. And I claimed that it was not a math joke but a joke for non-nerds to laugh at what they think of as the kind of thing nerds think of as funny.

I’m more idiosyncratic than most nerds. And I’m definitely not a “science nerd.” But I’ve spent most of my life in and around science, so I can pass. And when I came upon the following bit of computer code, I was amused:

int i;main(){for(;i["]<i;++i){--i;}"];read('-'-'-',i+++"hell\
o, world!\n",'/'/'/'));}read(j,i,p){write(j/p+p,i---j,i/i);}

A Computer Science Joke

Now a true computer science nerd would probably be able to explain all of this little bit of C code. But I can’t. I do, however, understand it enough to find it hilarious. For example, it pretends to increment through i and do nothing but decrement i. That is very funny. But it’s even more funny that it doesn’t actually do that. To even start to explain what I think it does would require knowledge that 99 percent of my readers don’t have. And it would take a long time to explain.

This was one of the winners of the first (1984) International Obfuscated C Code Contest. And part of the problem with this bit of code is probably found in the README about that year’s contest, “Restrictions against machine dependent code were not in the rules in 1984.” You see, one of the great things about C is that it is basically just a micro-step above assembly language. And compilers do allow you to take a normal variable and use it as a pointer to the memory address of that value. Hence, i["]<i;++i){--i;}"]. And where exactly "]<i;++i){--i;}" would point relative to the original memory address would indeed be machine dependent. (I told you that you wouldn’t understand.)

What Nerds Are Really Like

The thing is, when I was in graduate school, people were crazy about the Obfuscated C Code Contest. It’s similar to the way that grammar geeks love the sentence, Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo. This is what nerds do. Actually, this is what nerds are. Popular conceptions of nerds are based largely on what children who were into science acted like. It’s equivalent to assuming boiler techs must all punch women they like in the shoulder, because that’s what they did when they were six years old.

It’s this idea that has always made me hate films and plays about mathematicians: where’s the math?! Because, you know, for mathematicians, it really is all about the math. That’s not to say that they don’t have regular lives too. But the math is the reason anyone wrote a script. These things are like a film about Jacques Cousteau where he’s never on a boat.

All I’m asking is that society give nerds their due. I suppose that The Simpsons can be forgiven, because that particular “math” joke involved kids. But let’s be very honest: “i 8 sum pi” is what society thinks of us. And I hate society for it.

Brad Plumer wrote a disconcerting article over at Vox, NASA Images Show Utah’s Great Salt Lake Shrinking Dramatically. Over the last five years, Farmington Bay, which leads into the Great Salt Lake, has been reduced to one-quarter of its previous size. It’s basically just a river now. And this has huge environmental and economic ramifications.

(This is something that the modern world has forgotten. We are so focused on quarterly profits that we don’t see that most of the time economic and environmental interests go hand in hand. Interestingly, you would think that conservative economists would be most interested in this. But in general, they aren’t. Sure, they’re talk of externalities. But they aren’t much interested in it, because they are committed to having little government interference in the market. And dealing with externalities requires the government. Or business people who are enlightened — rarer than unicorns.)

No Mention of Global Warming

Brad Plumer is the guy at Vox who normally writes about global warming. But in this article, he didn’t mention the issue at all. Instead, he talked about the drought and the diversion of water. Currently 40 percent of all the river water flowing into the Great Salt Lake is diverted. Of course, that hasn’t changed. The real issue is the drought. And my question is: why the drought?

Now I get why Plumer didn’t mention global warming. There is no way to know if the current drought is due to global warming. But I think it is a mistake to get too caught up in what you can know for certain. For one thing, it just plays into the the denial industry. And as I have said many times before, the biggest issue with global warming is rainfall, not temperature.

Temperature-Rainfall Correlations

There has been a lot of work looking at temperature and rainfall correlation. My first year in graduate school, I shared a cubical wall with a young Chinese student. He looked at the last century of data for the United States. And it was frightening. The northeast had a positive correlation: more rainfall with higher temperatures. But everywhere else it was less rainfall with higher temperatures. And that was especially true out here in the west.

Note that just because there has been a correlation in the past, that doesn’t mean that global warming will cause the same effect. But as you may have noticed, we’ve been seeing drought in the west and very wet winters in the northeast. And it makes sense. So far this season in northern California, we’ve seen good rainfall. Most people are very hopeful. I’m not. I fully expect us to be below normal rainfall at the end of the season. That’s because I think “normal” rainfall is now a lot lower than it used to be.

Death of the Great Salt Lake?

So I think things are going to be very bad for the Great Salt Lake. They can stop diverting water and that will help. But my working theory is that they aren’t in the middle of a drought. They are just getting used to the new normal. And that new normal may be that there is no Great Salt Lake. It will be like the Owens Lake. But that one dried up due to the actions of the people who lived there. If the Great Salt Lake dries up, the culpability will be far broader.

When I was a kid, I was very interested in a lot of really silly things. I loved the film Chariots of the Gods? I even read the book and two of its sequels: Gods from Outer Space and The Gold of the Gods. Also, I was really into In Search of…, although long before its run was over I had seen the light. But all that stuff — Bigfoot, UFOs, the Bermuda Triangle — I loved into my middle school years. One thing I never went in for were the psychics.

Part of this was that I was into magic — as in slight of hand, conjuring — the art form. And psychics were such obvious frauds. That was especially true for people like Uri Geller and Kreskin — men who were standard mentalists (a form of performance magic) — who insisted that what they did was “real” instead of just tricks.

Celebrity Psychics

Even more pathetic were the newspaper and television psychics. At eight years old, I had them pegged. I always like what The Amazing Criswell says in the movie Ed Wood, “It’s horseshit… Eddie, there’s no such thing as a psychic. People believe my folderol because I wear a black tuxedo… Eddie, we’re in show biz. It’s all about razzle-dazzle. Appearances. If you look good, and you talk well, people will swallow anything.” That’s what these people were.

The best example of this during my life was Jeane Dixon. Each year, she would come out with dozens of predictions. Some of them were outrageous. And some were simply educated guesses. And later, she would talk about the predictions that she got right and ignore the far greater number that were wrong. Mathematician John Allen Paulos even coined a term for this, “The Dixon Effect.”

The Twitter Psychic

The Dixon Effect has never gone away. There have apparently always been psychics and there apparently always will be. And it is always the same con. But Twitter makes doing this sort of thing so much cooler! Check out this Tweet that went viral after the Cubs won the World Series in game seven in extra innings:

2016 World Series.

Cubs vs Indians

And then the world will end with the score tied in game seven in extra innings #apocalypse

— GIO (@RaysFanGio) November 4, 2014

As I write this, it has over 300,000 combined retweets and likes. And it’s understandable. Look at the date on it: 4 November 2014 — two years ago. Wow! GIO must be one amazing psychic or analyst or something, right?! Wrong.

How It Works

What people like GIO do is create a huge number of predictions on Twitter. And then, as each prediction goes wrong, they delete the tweet about it. By the time the actual event comes around, they are left with only the tweets that are right.

Aja Romano explained the whole thing over at Vox, That Viral 2014 Cubs World Series Tweet Seems Too Good to Be True. That’s Because It Is. She even provides an image of Noah Hiles doing this now: New York Mets 2017 WS Champs; Cincinnati Reds 2017 WS Champs; Milwaukee Brewers 2017 WS Champs; and so on.

What Jeane Dixon would have paid for such abilities: just make the wrong predictions go away! It’s really kind of brilliant. But it is, just as with Uri Geller and Kreskin, a magic trick. And now that you know how the trick is done, it loses its magic. Of course, for me, it’s totally cool. When I see a magic trick, I don’t go, “Wow!” I go, “Now let me figure out how that was done.” It’s really no different than solving a Sudoku puzzle.

I hope you will forgive me for writing about math today. Last night, I was lying in bed thinking about the numbers 7 and 11. I had been listening to a podcast with Ezra Klein and Molly Ball. Ball had mentioned that the number of white Christians in the United States had gone from (I think!) 54 percent when Obama came into office and that it was 47 percent now. Klein must have misheard her, because he later referred to it being an 11 percentage point drop. But that was why I was thinking about the two numbers — 7 percentage points is the actual number.

These numbers are interesting in that they are consecutive primes. And being so, they hold a certain fascination for me. But it got me thinking about the number 9. Nine is not a prime, since it reduces to 3×3. And then something occurred to me that I’d never thought about before: two odd numbers multiplied always create an odd number.

I know this is obvious, but since when has that ever stopped me? Why is it that odd numbers multiplied are always odd?

Multiplying Even Numbers

Let’s start with an easier question: why are even numbers multiplied always even? That’s almost definitional. An even number is any whole number divisible by 2. So if you have two even numbers x and y, you know that both x/2 and y/2 must be whole numbers. Thus, for example:

Note that it doesn’t matter if y is even. Thus: an even number times any number will be even.

Multiplying Odd Numbers

Looking at two odd numbers is more interesting. Or I think it is. Let’s stick with our variables above. Now we have two odd numbers: x+1 and y+1. If we multiply them, we get the following:

Given that x and y are even, we know that x×y is even. So we have: even plus even plus even plus one. The whole thing doubles back on itself: we defined our odd numbers as evens plus one. And that’s what we get here.

Using Addition

Another way to think about it is via addition. This is the way that ought to come more naturally. Multiplication is, after all, just addition. Four times three is just 3+3+3+3. Sadly, math is usually taught so badly that people don’t think in this way. So people end up thinking that addition, subtraction, multiplication, and division are four different things when they are all just one really simple thing: addition.

Thinking in this way, (x+1)×(y+1) would be the number y+1 added x+1 times. I would show you how this all works with a series, but doing so requires more typesetting ability than I have here. But think about it. If you add an odd number an even number of times, you will get an even number. So when you add that odd number one more time, it makes the even number odd.

The beautiful thing about math is that this is all intuitive. I didn’t have to work out the steps in my mind. It all looks awful on the page. In the mind, it’s comforting. Of course, I did have to get out of bed. I figured if I didn’t write down the idea, I would forget to write this article. Then wouldn’t you all be sorry…