void setup(){
    background(0);
    size(720,700);
    smooth();
}

void draw(){
    int x1 = ceil(random(0,height/2));
    int y1 = ceil(random(0,width/2));

    int x2 = ceil(random(0,height/2));
    int y2 = ceil(random(0,width/2));

    int x3 = ceil(random(0,height/2));
    int y3 = ceil(random(0,width/2));

    int h = height/2;
    int w = width/2;


    int r = floor(random(1,height));

    if (r > h){
        frameRate(r/2);
        fill(0);
        noStroke();
    }
    else{
        frameRate(r);
        fill(255);
        //stroke(0,0,0,20); //uncomment for more detail
    }


    triangle(w-x1,h-y1, w-x2, h-y2, w-x3, h-y3);
    triangle(w+x1,h-y1, w+x2, h-y2, w+x3, h-y3);

    triangle(w-x1,h+y1, w-x2, h+y2, w-x3, h+y3);
    triangle(w+x1,h+y1, w+x2, h+y2, w+x3, h+y3);
}