let position;

let mass = 50;

​

function setup() {

  createCanvas(640, 360);

  noFill();

  position = createVector(width/2, height/2);

}

​

function draw() {

  background(255);

  ellipse(position.x,position.y,mass,mass);

}

​

function keyPressed(){

  if (keyCode==LEFT_ARROW){

    position.x-=1;

  }

  if (keyCode==RIGHT_ARROW){

    position.x+=1;

  }

  if (key==' '){

    mass=random(15,80);

    position.y=-mass;

  }

}