BRG Christmas Card

Augmented reality card and app

For the Block Reasearch Group ETH

Zurich Switzerland


For our holiday card this year, we explored bringing 3D reciprocal diagrams into virtual reality! On the front of our holiday card, are planar projections of 3D reciprocal snowflakes. Using the “BRG XCard 2015” app, you will be able to see the holographic projections of the 3D reciprocal snowflakes in real-time! If you understand the frame-like snowflake as the structure (under given external loads, or equivalent self-stress), the forces within the bars of that structure are proportional to the areas of the corresponding, perpendicular faces of the solidlike snowflake.​


  1. Go to the front side of the card..

  2. On another device, download and install the “BRG XCard 2015” app from the Google Play.

  3. Open the App.

  4. Point the camera at the front of the image. Be sure to include the whole image in the viewing area.

  5. Wait until the image is tracked.

  6. Enjoy!