let ballX = 0;
let ballSpeed = 10;
function setup() {
createCanvas(500, 500);
}
function draw() {
background(50);
fill(200);
if (ballX < 15) {
ballSpeed = abs(ballSpeed);
}
if (ballX > 500 - 15) {
ballSpeed = -abs(ballSpeed);
}
ballX += ballSpeed;
ellipse(ballX, 250, 30, 30);
}