One of the things I have to do on a regular basis is run a suite of regression tests against Copilot’s payment system to ensure that we’re doing basic vetting of invalid credit cards, such as those that do not have valid Luhn checksums. To that end, I was very happy to discover a list of credit card numbers that I could use for testing purposes. The numbers aren’t for valid cards, but should pass any basic validation check you have in a commerce site you write.

There are few people in my life I admire more than my father. My father is the one who taught me how to swim, showed me my first BASIC programming, painstakingly explained algebra to me in fifth grade when I got annoyed at the confusing methods our my math teacher was teaching us, and demonstrated to me the value of problem-solving in high-anxiety situations when I was four by locking me in the child restraint seat and leaving me in the garage. I still turn to him when I’m in need of advice, support, or a good laugh.

Those who know me well know that I loathe Valentine’s Day. Part of that is just me being bitter—I’ve been in a stable relationship on Valentine’s Day exactly once—but a lot of it’s also that I don’t quite get why, on February 14th, everything is just supposed to be so much more hunky-dory than any other day. It’s a day created by card and flower companies to make sure you’re buying their products year-round, since otherwise, they’d have to go from Christmas to Mother’s Day without any real sales. If you really want to do something that will be romantically appreciated, in my experience, you’re much better off doing something random and out-of-the-blue when it’s least expected and your S.O. is feeling down than on a day whose main icon is a naked kid with bow-and-arrows who wanders around shooting people in the name of love. It’s like we have a whole holiday for John Hinckley.

So a few days ago, I was on the phone, whining to my dad about throwing a Fifth Annual F–- Valentine’s Day party and trying to figure out my personal life. My dad listened thoughtfully, and then began explaining to me what I was doing wrong.

The problem, he said, is that I date girls serially.

Let’s let V be potential difference between dating girls and doing something productive, I be current of love, and R be resistance to current flow. The problem with serial dating is the same as with serial circuits. If resistance starts to increase, you’re stuck: because V = IR, and R is increasing, I must decrease to hold the equality. Worse still, because P = IV, you’re just not going to have as much power with the increased resistance. Note on the above diagram that current is a lousy 214 mA, and we’re only able to get 1.93 “jewels” from our relationships. This is even worse than it seems: because there’s only one path—through all relationships—you’ll end up spending the majority of your energy on the relationship with the greatest resistance, which is exactly the opposite of what you want to do.

Worst of all, if (horror of horrors) you actually blow out one of your relationships, all current stops until you can manually patch things up. Your love life will be at least momentarily in ruins.

Now let’s examine the case where you’re dating multiple girls at once.

Even before we try the (admittedly more complicated) calculations, we can already tell the situation has significantly improved. Because we’re dating in parallel, we compensate automatically for higher resistance. Even though Lisa clearly is just not putting out, the result isn’t the massive slow-down we saw before, but instead results in conservation of energy, as you expend less effort on a mostly dead branch and focus instead on more promising branches. Whereas before, Lisa sucked the majority of our energy, now Sally and Judy do—at 16.2 and 9 jewels, respectively.

A broken circuit also no longer really fazes us. In the case that one of the relationships completely evaporates (which, let’s face it, Lisa’s not heading in a good direction), we’ve still got other branches to take up the slack. Best of all, because Lisa was high-resistance anyway, her departure barely affected net current, which decreases from 3.1 A to 2.8 A—both radically higher than net series current.

And with that simple metaphor, I suddenly felt much better about how things are going in my life right now. Dads are awesome.

So, in summary, dating serially is for chumps. If you really want to have a better fail-safe, be less affected by resistance, and have a wonderful net increase in power, go for parallel relationships. It’s the only way.

In the process of writing my column on transit system maps, I got distracted by a Wikipedia clickfest, and discovered the answer to a longstanding question I’ve had. The Q can indeed go further north than 57th St.—to 63rd and Lexington Avenue, as it happens, where it would one day be able to hand off passengers to the mythical and deadly T train (the always-not-quite-here-yet Second Avenue line). When that happens, I’d expect traffic on the Q to skyrocket.

Recently, on reddit, someone linked to a map of the US interstate system laid out “subway style.” Rather than including all the geographical features of the United States, the artist opted to realign everything on a relatively simple aligned grid, emphasizing the purpose of the system (“get me from here to there”) rather than the implementation (“via this bridge over this river, using this exit by this town”). The artist himself complains tongue-in-cheek about the complexity of the existing system:

You know, the Interstate System is a pretty incredible bit of infrastructure, but have you ever looked at a map? It’s all over the place! Did those civil engineers never hear of a ruler?

Perhaps such a map is a nice idea in practice, but in the name of becoming simple, the map loses so much information that it becomes nearly worthless. The elimination of any sense of scale leaves you no idea how long it will take to get between two points. The absence of any geographical information means you have no idea what conditions or weather you may encounter. The elimination of intermediate place-names means that you cannot get to a location not on the map, no matter how close it may be to places that are on the map, unless you already know the complex system that the simplified layout is trying to hide. In an attempt to isolate the reader from the complexity of the Interstate, the map has given up an overwhelming amount of what made that same Interstate useful to begin with.

This whole discussion may seem like an aimless rant. After all, no one is seriously proposing to replace our normal Interstate maps with this simplified design. Yet such systems already dominate major mass transit maps. Take a look at the maps for the Chicago “L”, the DC Metro, or the T in Boston. The maps all list place names, but street names and major landmarks are completely missing (except for the Loop insert on the Chicago map), and times can vary tremendously. (Stops on the DC map, for example, go from at least one minute to about five with no indication, and relative distances on the map can be horribly misleading. Judging by the map, Foggy Bottom to Court House should be the same time as Metro Center to Farragut North, with both among the longest inter-station travel times in the system. That’s not even close to being correct.)

The New York Subway map is better in some ways and worse than some ways than Chicago, Boston, and DC. Taking advantage of the fact that most parts of the city are on grid systems, the map emphasizes intersections over place names. Although the map still lacks any meaningful scale, the grid system is simple enough that even a newcomer to the city, with a minute or two instruction, could make at least a rough guess for travel times—at least in Manhattan north of Houston. Even here, though, the map falls short. If someone wants to get to downtown Manhattan or one of the outer boroughs, they’re stuck. The map does not include enough information to make rational decisions without consulting an additional, detailed, scale map, just as with the other systems.

Now take a look at onnyturf’s map of the New York Subway. The subways and their stops still stand out and are easy to find, but now the entire map is to scale. The lines no longer run graceful curves; instead, the small blips and squiggles of long-forgotten zoning fights and long-gone support pillars for defunct skyscrapers are there for all the eye to see. Yet, if anything, the map has actually become easier to use. Someone completely new to the New York Subway could make a decent guess about how to get from one point to another, even if he were trying to get to a place not on the official New York Subway map. The added complexity actually simplifies the utility.

Simplicity is a good thing, but the focus should always be on simplicity for the user, not of the item itself. Sometimes, making something simple to involves exposing its warts.

I hadn’t even heard of Rob Paravonian until over the weekend, when I went with a friend of mine to wander around Duke, but I’ve become an immediate fan. Anyone who’s ever played classical music has developed an intense loathing for Pachelbel’s Canon in D. The song is highly repetitive, playing the same melody over and over, in a giant, musical circle of pain, with only the most miniscule changes over its multitudinous repetitions. It’s like a three-year-old’s take on Bolero. Combine that with the fact that I used to date a cellist myself, and you have a recipe for laughter in Paravonian’s take on the Canon in D.