moveover_example.js

var x = 30;
var y = 30;

function setup() {
  createCanvas(400, 600);
  background(0);
}

function mousePressed() {
  ellipse(x, y, 20, 20);
  x = x + 30;
  if (x > width) {
    x = 30;
    y = y + 30;
  }
}