function setup() {

  createCanvas(500, 500)

}

var ufoY = 0

var ufodirection = 1

​

function draw() {

  background(28, 56, 99)

  fill(300)

  stroke(200)

  strokeWeight(3)

  ellipse(440,60,75,75) //moon

​

  //grass

  fill(42, 105, 66)

  stroke(0)

  strokeWeight(5)

  rect(-100,350,1000,400)

  //ufo

  push()

  translate(0,ufoY)

  strokeWeight(4)

  stroke(0)

  fill(91, 99, 93)

  ellipse(250,130,175,75)

  fill(161, 161, 161)

  ellipse(250,124,175,60)

  fill(153, 204, 197)

  ellipse(250,110,75,60)

  fill(300)

  strokeWeight(0)

  ellipse(232,100,20,20)

  ellipse(243,90,10,10)

  pop()

  //movement

  ufoY = ufoY + 0.25 * ufodirection

  if(ufoY > 20 )

    {

      ufodirection = -1

    }

  if(ufoY < 10 )

    {

      ufodirection = 1

    }

}