function iterate() {
    context.clearRect(0, 0, canvas.width, canvas.height);
    let detections = 0;
    if (mouseIsDown) {
        let velocityX = Math.random() * (100 + 50) + -50;
        let velocityY = Math.random() * (100 + 50) + -50;
        let x = mouseX;
        let y = mouseY;
        let r = 10.0;
        if (x + r > canvas.width) {
            let change = (x + r) - canvas.width;
            x -= change;
        } else if (x - r < 0) {
            let change = Math.abs(x - r);
            x += change;
        }
        if (y + r > canvas.height) {
            let change = (y + r) - canvas.height;
            y -= change;
        } else if (y - r < 0) {
            let change = Math.abs(y - r);
            y += change;
        }
        balls.push(new ball(x, y, r, velocityX, velocityY));
    }
    let quadTree = new QuadTree(boundaryAABB);
    for (let c of balls) {
        c.isColided = false;
        quadTree.insert(c);
    }
    for (let c of balls) {
        let searchedAABB =  new AABB(c.x, c.y, c.r + 1);
        let foundballs = quadTree.queryRange(searchedAABB);
        for (let fb of foundballs) {
            if (c == fb) {
                continue;
            }
            detections++;
            if (c.intersects(fb)) {
                c.isColided = true;
                fb.isColided = true;
                break;
            }
        }
    }
    quadTree.draw(context, drawGridCheckbox.checked);
    d = new Date();
    changeTimeS = (d.getTime() / 1000.0) - lastTimeS;
    lastTimeS = d.getTime() / 1000.0;
    for (let c of balls) {
        let nextX = c.x + c.velocityX * changeTimeS;
        let nextY = c.y - c.velocityY * changeTimeS;
        if (nextX - c.r <= 0 || nextX + c.r >= canvas.width) {
            c.velocityX *= -1;
            c.x += c.velocityX * changeTimeS;
        } else {
            c.x = nextX;
        }
        if (nextY - c.r <= 0 || nextY + c.r >= canvas.height) {
            c.velocityY *= -1;
            c.y -= c.velocityY * changeTimeS;
        } else {
            c.y = nextY;
        }
    }
    ballCounter.textContent = balls.length;
    detectionCounter.textContent = detections;
    bruteforceCounter.textContent = Math.pow(balls.length, 2);
    ratio.textContent=Math.round((Math.pow(balls.length, 2)-detections)/(detections))
}