Nintendo specifically designed its Wii U GamePad controller to work in a variety of circumstances, but at least one engineer wished they wouldn’t add motion games to the list of potential complications.

With the Wii U and its tablet GamePad controller, out Nov. 18 for $299.99, you play a game on the television while viewing important information on the handheld display. More impressive than that, you can simultaneously press the + and – buttons to have the primary screen moved to the tablet’s LCD panel so that someone else can use the TV. The Wii U accomplishes all of this by sending video data wirelessly to the controller.

Nintendo wants that functionality to work while also using the GamePad for motion games.

And that’s the problem.

“It’s extremely tough, wirelessly, to have players hold the Wii U GamePad and move with it because of the Doppler effect,” Nintendo product development engineer Kenichi Mae said in an “Iwata Asks” feature on Nintendo’s website.

“To be honest, I even thought, ‘No, please don’t!'” Mae said about Nintendo’s plans for motion games on the Wii U.

For those who skipped your high school science class, the Doppler effect is when differences in relative speed between the source of waves and the receiver of those waves causes a distortion. It’s the phenomenon that causes a police siren to sound different depending on whether the police vehicle is approaching or leaving your location.

That same kind of distortion can happen in the radio waves sent between the Wii U and the GamePad if players are waving around the controller … which they will in games like Nintendo Land.

Mae and fellow engineers didn’t mention exactly how they overcame this obstacle, but they seem confident that it shouldn’t pose a problem in the final product.