The half mirror is self made. The glas is cut from a photo picture frame, and a sun shield / privacy foil was applied.
==== How it works ====
The following animation shows, from the side, the light-path for the upper half of the half mirror. The blue lines are the retroreflectors, the green line is the half mirror.
==== Gallery ====
<gallery mode="packed-hover">
image:HoloDings1.jpg
==== External links ====
http://www.k2.t.u-tokyo.ac.jp/perception/AIRR_Tablet/index-e.html