//
void setup() {
	frameRate(30);
	loop();
}

//var ctxt = get2DCanvas("hcanvas");
float x=0;
int rl=round(random(100));
void draw() {
	clear(x-1,0,2,height);
	drawLine();
	if (randTrigger()) drawDot();	
}
void drawLine() {
	stroke(120,0,0,30);
	++x;
	if (x>=width) x=0;
	line(x,1,x,height);
}
void drawDot() {
	float randy = random(height);
	noStroke();
	fill(150);
	rect(x-3,randy,4,2);
}
boolean randTrigger() {
	if (rl<=0) {
		rl=round(random(100));
		return true;
	}
	--rl;
	return false;
}