let rectHeight;

let rectX, rectY;

let speed = 1;

​

function setup() {

  createCanvas(400, 400);

  rectWidth = width/4;

  rectHeight = height/4;

  rectX = 0;

  rectY = height/2;

}

​

function draw() {

  background(220, 10);

  line(width/2, height/2, mouseX, mouseY);

  //

  fill(255)

  ellipse(width/2, height/2, 200, 200);

  fill(255,0, 255);

  circle(mouseX, mouseY, 50);

​

  rectMode(CENTER);

  stroke(255, 0, 255)

  fill(255,0, 255);

  rect(rectX, rectY, rectWidth, rectHeight);

  rectX = rectX + speed;

  if (rectX > width){

  rectX = 0;

  }

}