Among its imperfections, and some New Yorkers will tell you there are many, the city's official subway map does not distinguish between local and express lines that hopscotch many stops.

If you're the kind of person — someone not overly attuned to fine print — who boards a Bronx-bound D train expecting to hop off at the Museum of Natural History, this is a design problem.

Tommi Moilanen, a Finnish user-experience designer in New York, decided to correct the flaw (and a number of others) as a long tradition of designers and artists have: by redrawing the entire map. His version is more minimalist than the current MTA map, ditching the geography of the city above ground for a spare emphasis on each subway below, including the differences between the express (thick) lines and local (thin) ones:

A subway map is a special kind of puzzle — infinitely alterable, incredibly vexing, with no definitive answer — which explains why someone like Moilanen, who does not work for the Metropolitan Transportation Authority, would spend his own time trying to solve it. A subway map demands that much information be crammed into very little space, and in a way that might be intuitively understood by commuters on the run. It embodies tension: between beauty and utility, abstraction and accuracy, completeness and simplicity.

Decisions must inevitably be made to emphasize one line over another, or to prioritize one part of town. Or to create, more than a functional tool, a piece of frame-able artwork. That means, also inevitably, that people somewhere won't like the outcome. And someone out there will raise his hand to redesign it.

"It’s almost an impossible conundrum in some ways," says Mark Ovenden, the British author of the newly updated "Transit Maps of the World," a book that contains nearly every subway map in the world, official and otherwise.

New York's system presents the biggest conundrum. It has more stops than any other subway in the world. And the network is layered with extra complications between local and express service, weekday and weekend routes. If it is not possible to truly design a perfect subway map, it is definitely impossible to perfect this one. This diagram of the system from 1958 was, at that time, the simplest map available for the whole network:

From half a century earlier, in 1904, here is a more geographically literal map of the rail lines in Manhattan:

"I don’t think there will ever be a map that everyone likes," Moilanen says in an e-mail, "but that is not even the right question to ask. The right question is does it do its job by being easy to use and also, does it look the part. Does the map look like it belongs to New York and to its subway system."

The free-flowing lines on the current MTA map, last significantly revised in 1979, feel oddly whimsical, and the entire look, Moilanen adds, appears dated. His map, in contrast, is designed to reflect all the gray tones and bare metal of the subway system itself, as well as the iconic signage that Massimo Vignelli created for it in the 1960s. The borough names on Moilanen's map, in Helvetica in the background, are supposed to be a little brash, like New York itself.

His version evokes the famous 1972 Vignelli revision, beloved by designers but panned by average riders who had trouble actually using the thing. Vignelli's map largely dispensed with geographic accuracy in converting the entire system into a clean diagram of parallel lines and right angles. The result, as Ovenden puts it, shows that "it’s perfectly possible for things to be beautifully designed but not very good for practical use."

The most novel redesigns of any system are entirely detached from the limits of geography. This Max Roberts map envisions New York's system around geometry rather than geography:

Here is Chicago's "Loop" envisioned with an actual loop at its center...

... and a playful rendering of what Washington's metro might look like as a spiral:

These aren't so much serious revisions as maps playfully re-envisioned as optical illusions. But their existence reinforces the notion that there is something about the subway map that invites iteration, that lures designers again and again. Road networks don't do this. Airport networks don't, either. The map at the back of every airline magazine has more or less converged on the same style. Highway maps are standard, too, because the rules and universal symbols of cartography make them so.

There are so many fantastical, plausible, complicated, minimalist, abstract, artful versions of transit maps precisely because there are few rules, suggests Cameron Booth, who runs the Transit Maps tumblr. "It's this multiplicity of valid solutions to a very simple problem ('How do I get from here to there?') that makes this field of design so interesting and compelling to me," Booth writes in an e-mail.

And many designers, he says, are simply drawn by a belief that an existing map is, well, bad. That's why, Booth says, he redrew D.C.'s Metro map circa 2010:

He took the liberty of doing the same favor for Boston in 2012:

But design, Booth acknowledges, is so subjective: "So there'll always be at least one designer out there who looks at a particular map and says, 'I can do better than that!'"

As surely someone will do with Moilanen's reinterpretation of New York's subway.

The appeal of improving these maps, Ovenden suspects, also has something to do with the subway itself and what it means to us. "You’re in a car with all these other users, some of them are rich, some of them are poor, some are beautiful — and you're all in it together," he says. "And I think that’s the great thing about trains. We are all using this common system together, and it’s very kind of leveling. We all want it to be better. And we want it to run more frequently, more smoothly, with less problems. We have a love-hate relationship, and an enormous desire for it to work better."

Little wonder that many people would like to think they can, at least, improve the part of the system that's open to our tinkering: the map.