let y;

​

function setup() {

  createCanvas(400,400)

  x=200; 

  y= 200;

  //initialized

}

​

function draw() {

  background(220);

  //ellipse(200,200,20,20)

  ellipse(x, y ,20,20)

  x++;

  y++;

  //x = x + 1;

  //x += 1;

  //they are smae things 

  //x++ is increment and it always increase by 1 but x += 1 is you can change the number. x = x + 1;x is generic algorithm. 

}

​