const ball = {
    x: 200,
    y: 200,
    size: 0,
    speed: 1,
};

function setup() {
    createCanvas(400, 400);
}

function draw() {
    background(255);
    strokeWeight(2);
    fill(ball.size, 0, 0);
    star(ball.x, ball.y, 100, ball.size, 5);

    ball.size += ball.speed;
    ball.speed *= 1.5;

    if (ball.size >= 200) {
        ball.size = 200;
        ball.speed = -1;
    }

    if (ball.size <= 0) {
        ball.size = 0;
        ball.speed = 1;
    }
}

function star(x, y, radius1, radius2, npoints) {
    let angle = TWO_PI / npoints;
    let halfAngle = angle / 2.0;
    beginShape();
    for (let a = 0; a < TWO_PI; a += angle) {
        let sx = x + cos(a) * radius2;
        let sy = y + sin(a) * radius2;
        vertex(sx, sy);
        sx = x + cos(a + halfAngle) * radius1;
        sy = y + sin(a + halfAngle) * radius1;
        vertex(sx, sy);
    }
    endShape(CLOSE);
}