Just press play and watch. You can change how often raindrops fall by clicking on the gear in the bottom right and adjusting the slider that appears (higher numbers = less drops). Click on the gear again to hide the slider.
I got inspired by the song (which is by James Roach, an awesome composer). I thought it sounded like something that might play on a rainy night in a game. (Note: the rain sounds aren't actually part of the song.) Fun fact: there is a very loud and windy thunderstorm outside as I write this, and it's awesome. Storms are so cool! (And, apparently, I completely slept through another one last night. When I actually fall asleep, I sleep like the dead.) Music is a commission draft by James Roach (https://soundcloud.com/jamesroachmusic) (warning: some of his track titles contain profanity.). All art and coding by me. Why do I keep making projects of stuff falling? First snowflakes, now this... Update Log: 05/06/2017: Shared.