I was inspired by Tom Scott’s excellent video and links here https://www.youtube.com/watch?v=d99_h30swtM

where he talks about a particular type of “Inogon” light used to guide ships through channels or harbours.

The patent is here: https://patents.google.com/patent/US4629325 and the military report on the effectiveness is here: http://www.dtic.mil/dtic/tr/fulltext/u2/a168108.pdf

(Hint; They don’t seem to like it much).

I decided to build my own to play around with the effect. After a few minutes sketching in inkscape and a few more lasercutting, I had this:

I followed the claims in the patent fairly closely.…