var red_circle_y = 35;

var blue_circle_x = 100;

var blue_circle_y = 35;

​

var diameter = 50;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(235);

  noStroke();

  fill(255, 0, 0);

  circle(red_circle_x, red_circle_y, diameter);

  fill(0, 0, 255);

  circle(blue_circle_x, blue_circle_y, diameter);

}

​

function mouseDragged(){

  if (mouseX > red_circle_x - diameter && mouseX < red_circle_x + diameter){

    if (mouseY > red_circle_y - diameter && mouseY < red_circle_y + diameter){

      red_circle_x = mouseX;

      red_circle_y = mouseY;

    }

  } 

  else if (mouseX > blue_circle_x - diameter && mouseX < blue_circle_x + diameter){

      if (mouseY > blue_circle_y - diameter && mouseY < blue_circle_y + diameter){

        blue_circle_x = mouseX;

        blue_circle_y = mouseY;

    }

  }

}