Tokyo installed see-through public toilets in a park to let people inspect their cleanliness before using them.

[Robert59]

Tokyo installed see-through public toilets in a park to let people inspect their cleanliness before using them, at which point the glass turns opaque
https://www.yahoo.com/news/tokyo-installed-see-public-toilets-101404243.html

 

[peramangkelder]

 

[Sunny]

Well, as long as you can COUNT on that opaque part of it!

 

[Aunt Bea]

We had smart glass panels like that in some of the conference rooms where I worked. If you flipped a light switch the wall of glass would turn white and when the switch was turned off the window would be clear. I think that the electric charge worked with some sort of magic dust particles inside the double pane of glass.

 

[fmdog44]

I'll stick with drilling a hole in the wall. Old school has always worked for me.