Projecting the image from a vehicle's blind spot onto its A-pillar. 8th grade Science and Engineering Fair project by Alaina Gassler. 1:08 video:
https://www.youtube.com/watch?v=HxlNkIwqGb4
Previously:
https://www.homemadetools.net/forum/...192#post134695
https://www.homemadetools.net/forum/...842#post133525