let x = 50;

  let y = 50;

​

function setup() {

  // Code to create a 400x400 canvas

  createCanvas(400, 400);

}

​

function draw() {

  // Code to draw a gray background

  background(220);

  // Code that changes the position of the shape over time

  x++;

  // Code to draw the shape

  rect(x, y, 50, 50);

​

  // Code that describes mouse interaction

  if(mouseX > x && mouseX < x + 50) {

  x = mouseX;

}

​

}