Tenish years ago I wrote a pseudorandom number generator from webcam stills. Since I wrote the code in the middle of a midwestern winter, my first solution was

Tenish years ago I wrote a pseudorandom number generator from webcam stills. Since I wrote the code in the middle of a midwestern winter, my first solution was a shot of the outside; falling snow. When the snow started to slow down, I moved to using a lava lamp. So to answer your question...falling snow works really well juxtaposed against clouds.