Cardboard Design Lab

Google Cardboard is a very interesting project that can transform pretty much any modern smartphone into a device that can provide at least a limited VR experience. Whereas most companies chose to make proprietary hardware, Google went a different and more simple route.
 
Cardboard Design Lab is an application that shows people just how easy it is to build a virtual reality experience, even how to implement it in an application. Unlike the design of a 2D application, a 3D experience is much more complicated and take more effort.
 
The application covers virtually all of the required goals, such as using a reticle, eye strain, UI depth, head tracking, light guiding, spatial audio, and much more.