Open the untangle.data.js file in the text editor.

Add the following circle object definition code in the JavaScript file:

untangleGame.Circle = function(x,y,radius){
  this.x = x;
  this.y = y;
  this.radius = radius;
}

Now we need an array to store the circles' positions. Add a new array to the untangleGame object:

untangleGame.circles = [];

While drawing every circle in the Canvas, we save the position of the circle in the circles array. Add the following line before calling the drawCircle function, inside the createRandomCircles function:

untangleGame.circles.push(new untangleGame.Circle(x,y,circleRadius));

After the steps, we should have the following code in the untangle.data.js file:

if (untangleGame === undefined) {
  var untangleGame = {};
}

untangleGame.circles = [];

untangleGame.Circle = function(x,y,radius){
  this.x = x;
  this.y = y;
  this.radius = radius;
};

untangleGame.createRandomCircles = function(width, height) {
  // randomly...