var Yes = [];

​

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

  for (var i = 0; i < Xes.length; i++) {

    rect(Xes[i], Yes[i], 10, 10);

  }

}

​

function mouseClicked() {

  //console.log(mouseX);

  //console.log(mouseY);

  Xes.push( mouseX );

  console.log(Xes)

  Yes.push(mouseY);

  console.log(Yes)

}