Turtle snow fall
From JSXGraph Wiki
References
The source code
function side(size, level) {
if (level==0) {
t.fd(size);
} else {
side(size/3, level-1);
t.lt(60);
side(size/3, level-1);
t.rt(120);
side(size/3, level-1);
t.lt(60);
side(size/3, level-1);
}
}
function snowflake(size, level) {
for (var i=0; i<3; i++) {
side(size, level);
t.rt(120);
}
}
t.ht();
function snow() {
counter++;
if (counter>500) {
counter = 0;
t.cs();
}
t.setPos(Math.random()*600-300,Math.random()*600-300);
snowflake(30*Math.random(),Math.floor(Math.random()*4));
active = setTimeout(snow,200);
}
t.setPenColor('#ffff00');
counter = 0;
snow();