On a recent visit to the Lab, I got an early look at Monster Moves, a new app that lets kids choreograph moves for a team of dance-happy monsters. If that conjures images of elaborate 3D creatures, think again. At first glance, Monster Moves appears to be completely flat. Any single frame of the game looks just like a simple 2D illustration.

But when one of those 2D monsters does a twirl or flip, suddenly (and pretty magically), you see that each one has a complete three-dimensional physiology, from the top of its head to the booty it’s shaking.

It might seem hardly noticeable, but think about it: if the image were truly two-dimensional, there would be no top or bottom, no back or sides. To make the monsters look flat while still allowing them to rotate 360°, the team used 3D modeling to create the characters, then stripped down the art to make them look two-dimensional. Even though they appear flat, all the monsters have skeletons and skins, and they can turn to any angle.

So why bother making them look flat?

Play Lab’s Design for Play Lead, Michelle Lee, explains that the game’s 2D look is crucial to its functionality. The mission of Monster Moves is to help kids understand that they are the choreographers and that their choices directly influence the monsters’ dance steps, fostering an awareness of creative control. The designers wanted kids to focus on the dance moves, so it was important that the art not distract them with too much 3D detail. That’s why they stripped away all the fancy shadows and shiny curves and kept the monsters as simple as possible.

The early version (left) has a 3D look, which the designers thought was still “too much.” They chose to eliminate all shadows except for the drop shadow beneath the character (right).

Learn more about the Monster Moves story in this Case Study on IDEO.com.