One afternoon last week, my Twitter feed began whispering: "Monument Valley, Monument Valley." The game had flown under my radar, and I noticed that even some of the most savvy followers of video games hadn't picked up on it yet, either. By the next night, my feed became a constant stream of love and excitement for Monument Valley, a game that many people had just learned about in the past 24 hours. It would soon top the paid App Store chart. Monument Valley is a game developed by a UK-based design firm called Ustwo, which has clients ranging from Tesco to Google. The company employs 200, but a game development team formed last year consists of just eight. One of those eight is Ken Wong, lead designer on Monument Valley, a visually-striking puzzler that exists as much as an interactive piece of art as it does an iPad game. The game's mechanics revolve around pushing, pulling, and shifting pieces of buildings, evoking a tactile, toy-like Lego quality. Its clean lines are unmistakably inspired by the impossible constructions conveyed in M.C. Escher's work. While some developers fall into the trap of trying to figure out what some theoretical audience wants in a game, Wong says he and his team, quite consciously, did not define a target audience. He did want to make a game involving architecture, so he worked towards making that game exist. "I was looking at some M.C. Escher art, and that led to me to think about making a game that's just about getting from the bottom to the top of a building," he says.

Ustwo, which specializes in user interface design, is a company full of people who, naturally, know a lot about design, and how design works on a mobile device. But not everyone at the 200-person company plays video games, Wong says. That led him to the question: "Why don't some people play games?" "We thought that there is no point in making games that they won't appreciate," he says. "So when we were designing, we always kept in mind, 'How is this going to appear to 'normal' people -- to non-gamers.'" From the beginning, Wong and the game dev team at Ustwo identified a couple oft-observed reasons for a "normal" person's disinterest in games: Games are typically very hard, and often very time-consuming. Monument Valley would address those concerns, without dumbing down the experience. Wong also wanted to make something visually-appealing, something that would draw people in, just at a glance. And he wanted to make a game that was a complete experience, one that could actually be finished ("We only added a level if we had something new to say," he says). It also wouldn't be free-to-play, rather it'd be a pay-once transaction. "Anybody going into such a competitive marketplace [to make a living], they have to have a game plan," says Wong, who encourages small teams to not only think as developers, but also as entrepreneurs. "How are we going to stand out in the marketplace? What are our unique selling points?" he asks. "Putting together a product, or a work of art, is a combination of having something personal to say or special to share, but also knowing how to say it in a way that people will understand, and positioning it in a way that's easy for people to get into," Wong adds. "Monument Valley is designed to show its hand from the get-go -- everything that's great about the game can be gleaned from the screenshots and the trailer." "We didn't have to put any money into marketing or advertising, because we felt that there was no better way to sell the game than to get the images and the trailer out there," he says. The fact that the game is so visually appealing becomes more understandable once I learn that Wong's 10-year game industry background includes work as an art director on games including Alice: Madness Returns, and his own iPhone game, Hackycat. This background in visual arts melds effortlessly with his game design goals in Monument Valley. "We have this concept that I call 'little worlds,' where you have an enclosed form which is floating in a space, within a frame, like a little maze or little sculpture surrounded by water or air or just gallery space," he says. "I looked up every example of something like that. So I looked at a dollhouse, or architectural models -- anything where you could see a whole building or whole system or just a composition all at once."

The game's levels draw from Middle Eastern, Indian, and Arabian architecture. Each little world exists in whole on the screen, transformed by the player's finger, as they guide a princess called Ida to the top of a building. "We're so used to having scrolling levels, for good reason -- you can explore a really wide world like that," says Wong. "But by constraining ourselves, by saying every screen is going to be a work of art that you can hang on a wall, we're going to add this additional condition, that every level has to look like a piece of graphic design. That forced us to come up with slightly different puzzles and slightly different levels." In the days since Monument Valley's iOS launch (it's due out on Android as well), people have expressed fascination as to how someone can conceptualize such level design, and put it in a finished product. Most games don't explore impossible geometry, and spatial scenarios the way games like Fez, Echochrome, Antichamber and Monument Valley do. "It's just design process, really," says Wong. He imagines that movies like Inception or Memento came together in a similar way to Monument Valley, as they play with space and time in fantastical ways. "We spent 10 months coming up with these levels," he adds. "It's interesting -- at the beginning of the project, there was this assumption that only I would be able to design levels. But by the end, there were two additional programmers who were, along with me, the main level designers." "You just get used to thinking in terms of impossible geometry. ... A lot of people, their first reaction to seeing Monument Valley is 'Oh, you guys must really like M.C. Escher,'" says Wong. "And you know, he's the most famous example. But if you have an interest in art, geometry, and math, then it naturally brings up these kinds of paradoxes. Antichamber is one example, Fez is another."

Monument Valley is an amalgamation of various artistic inspirations, from M.C. Escher's work to Fez to architecture to modern graphic design. Even the David Bowie movie Labyrinth influenced the game. These all came together in a well-executed game that has struck a chord with a wide audience, whose attention is being vied for from every angle. The game is very deliberately unique. Making uniqueness a design goal raised some natural design challenges for Wong: there was no genre for Monument Valley to follow. There was no Mario or Call of Duty to use as a template. Wong says his team had to get down to the essence of what games are. To him, that laid the foundation for Monument Valley's success. "We had to go back to the basics of what a game experience is," he says. "What's really important is to acknowledge that games are experiences. Interactive experiences. Interactivity is the key thing about them."