let y=0

let speedX=1

let speedY=1

​

function setup() {

  createCanvas(400, 400,WEBGL);

}

​

function draw() {

  background(220);

    push()

  translate(x,y,0);

  rotateX(frameCount*0.01)

  rotateY(frameCount*0.01)

  box(50)

  pop()

  x=x+speedX

  y=y+speedY

  if(x>width/2){speedX=-1}

   if(x<-width/2){speedX=1}

   if(y>height/2){speedY=-1}

  if(y<-height/2){speedY=1}

}