var x =70; 

var yChao = 300; 

var y = yChao; 

​

​

function setup() {

  createCanvas(400, 400);

  frameRate(30);

}

​

function draw() {

  background(30);

  stroke(255);

  fill(100);

  rect(0,yChao+5,400,100);

  fill(230)

  ellipse(x,y,30,40);

  if (keyIsDown(RIGHT_ARROW)){

    x = x + 6;

  }

  if (keyIsDown(LEFT_ARROW)){

    x = x - 6;

  }

}