Yeah its pretty simple yet very much not trivial. You can get images that are relatively fine by just making one from cardboard even. All you need is 4 mirrors. Two pairs for one side and two for the other. The non trivial part is how to fill the whole sensor frame and what specific angles to use for your specific lens. I'm using a 40mm lens full frame. 35mm can see the inside of the adapter so that's not good. It gets worse with the wide lenses on your phone, but you can still get an image you can crop. And its its really freaking cool to see your kids and family in 3D on your phone on a finished image. Unfortunately my family runs from the camera and doesn't get the 3D effect at all..and doesn't even want to try. But whatever. Maybe one day when I'm long gone, one of their kids will find an old rusty SD card and discover the awesome thing that 3D is. I don't understand why all the 3D headset makers haven't jumped on this with a standard....simple, have all new phones get 2 cameras, and then create the software to take the images or video. Finally have that video in a standard format for all viewers. There's plenty of smart people that can do this.

Oh and yes, you can do 3D video and it kicks wide angle viewed video so so much. It's phenomenal to watch my kid slide down a slide in 3D. I know it sounds stupid but man....the possibilities for the right open minded community are endless.