createCanvas(400, 300);

}

​

let x = 200;

let y = 150;

let speed = 1;

let gravity = 0.9;

​

function draw() {

  background(0);

  fill(255, 120);

  noStroke();

  ellipse(x, y, 50);

  if(y >= height) {

       speed = gravity - speed;

    }

  if(y < height){

     speed = speed + gravity;

   }

   y = y + speed;

}