How did TNG do those simple static animation LCARS?

[MangyDog]

https://youtu.be/QpDEKuHMBKo?t=55

Heres a clip from naked time showing the effect.
But in TNG they did this kind of effect a lot on background LCARS to look like functional displays. Obviously its a static decal with a simple back light...

But how did they do the flowing sequence effect on the static images?

Some one suggested its actually a camera trick, that in person you cant actually see it but something is going on that has it slightly out of sync form the camera...

one other option could be a simple LCD filter?

Anyway anyone know for sure what it is?

 

[ivanj05]

http://wrathofdhanprops.blogspot.com/2018/06/okudagrams-part-iii-why-they-seem-to.html

Hope this helps some.

 

[Mike J.]

Yeah, I remember seeing some science museum displays like that back in the 80's-90's.

 

[MangyDog]

Ooooohhhhhhh polarised filters... Now that makes sense... OK cool thanks