[niftich]

See also this post: https://news.ycombinator.com/item?id=12166332#12170616

Link reproduced for clarity:

[1] http://thruglassxfer.com/

[2] Demo of above: https://www.youtube.com/watch?v=2_8GlFdlb0Y

[3] Same idea, some hackable code: https://github.com/Neohapsis/QRCode-Video-Data-Exfiltration