Dan, You attributed to me a post made by WDS. -- Gene From: Dan Asimov <asimov@msri.org> To: Eugene Salamin <gene_salamin@yahoo.com>; math-fun <math-fun@mailman.xmission.com> Sent: Friday, June 12, 2015 4:30 PM Subject: Re: [math-fun] one way window for light Interesting — I never knew how "one-way mirrors" worked, just assumed it was some cheap trick. Many times finding myself unkempt on a sidewalk I've combed my hair in the window of adarkened shop, which works very well as a mirror. At times when I've been able to sidle up to the "opaque" side of a one-way mirror,it's clear when you're close enough (you can see through it). —Dan On Jun 12, 2015, at 2:42 PM, Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote: "One way mirrors" seen in police interview rooms on TV, aren't really. Light goes both ways through them, it is just that there is a lot less light coming from one side, since it is a dark place. The other side is brightly lit; and then if you partially-silver the window the scattering and partial reflection tends to overwhelm the transmission from the dark side, making it *appear* to be a mirror from the bright side.