Let it snow!

A couple days ago I noticed a fun piece of R code by Allan Roberts, which lets you create a digital snowflake by cutting out virtual triangles. Go give it a try. Roberts inspired me to create a whole night sky of snowflakes. I tried to make the snowfall look as organic as possible. There are lots of options to adjust. Here’s the code, have fun and Happy Holidays!

# Code by Matt Asher for statisticsblog.com
# Feel free to modify and redistribute 
# How many flakes do you want to fall?
flakes = 100
# Width and height of your space
width = 800
height = 600
# Initial wind
wind = 0
# Setup the background of the plot and margins
par(bg = "black")
plot(0, 0, col="black", pch=".", xlim=c(0,width), ylim=c(0,height), axes=F)
for(i in 1:flakes) {
    startY = height
    startX = runif(1,1,width)
    xPos = startX
    yPos = startY
    for(j in 1:height) {
		# Optional drift in wind
		wind = wind + rcauchy(1,0,.05)
		# Update snowflake position
        xPos = xPos + rnorm(1,.1,1.5)
        yPos = yPos - runif(1,4,20)
        # Are we in the space, if so display it
        if(xPos > 0 && xPos <= width && yPos > 0 && yPos <= height) {
            points(round(xPos), round(yPos), col="white", pch=8)
            # System dely, slows down the flakes

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  1. Your code got messed up a bit when copying it to the blog (if statement at the end). Here’s a version ready for copying into R: https://gist.github.com/4298885

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