I didn't see it anywhere, it was just an idea i had when i saw for the first time some shadow on the water. (probably then its an original idea! (OMG i'm a scientist!! OMG i discovered the HOT WATER!! 
lol )
It is simple but effective: just put a layer of normal blocks (a gray i think is better) and on this another layer of water. Then at any height put your "draw". The double shadow resulting will produce a nice LCD effect.
Here a screen shot of a simple 7-segment LCD i just did in guest world
lol )It is simple but effective: just put a layer of normal blocks (a gray i think is better) and on this another layer of water. Then at any height put your "draw". The double shadow resulting will produce a nice LCD effect.
Here a screen shot of a simple 7-segment LCD i just did in guest world