var arr = new Array(rows); //like arr[]; but with number of columns hardcoded

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

    arr[i] = new Array(cols);

  }

  return arr;

}

​

let angle = 0;

let w = 100;

let cols;

let rows;

let curves;

​

function setup() {

  createCanvas(800, 800);

  cols = floor(width / w) - 1;

  rows = floor(height / w) - 1;

  curves = make2DArray(rows, cols);

​

  for (let j = 0; j < rows; j++) {

    for (let i = 0; i < cols; i++) {

      curves[j][i] = new Curve();

    }

  }

}

​

function draw() {

  background(220);

  let d = w - 0.2 * w;

  let r = d / 2;

​

  // horizontal circles

  stroke(0);

  noFill();

  for (let i = 0; i < cols; i++) {

    // circles

    let cx = w + i * w + w / 2;

    let cy = w / 2;

    strokeWeight(1);

    stroke(0);

    circle(cx, cy, d);

​

    // points on circles

    x = r * cos(angle * (i + 1) - HALF_PI);

    y = r * sin(angle * (i + 1) - HALF_PI);

    strokeWeight(8);

    stroke(0);

    point(cx + x, cy + y);

​

    // animated line

    //strokeWeight(1);

    //stroke(0, 50);

    //line(cx + x, 0, cx + x, height);

​

    // add point to curves

    for (let j = 0; j < rows; j++) {

      curves[j][i].setX(cx + x);

    }

  }

​

  // vertical circles

  stroke(0);

  noFill();

  for (let j = 0; j < rows; j++) {

    // circles

    let cx = w / 2;

    let cy = w + j * w + w / 2;

    strokeWeight(1);

    stroke(0);

    circle(cx, cy, d);

​

    // points on circles

    x = r * cos(angle * (j + 1) - HALF_PI);

    y = r * sin(angle * (j + 1) - HALF_PI);

    strokeWeight(8);

    stroke(0);

    point(cx + x, cy + y);

​

    // animated line

    //strokeWeight(1);

    //stroke(0, 50);

    //line(0, cy + y, width, cy + y);

​

    // add point to curves

    for (let i = 0; i < rows; i++) {

      curves[j][i].setY(cy + y);

    }

  }

​

  // add point to curve and draw

  if(angle < TWO_PI)

  {

  for (let j = 0; j < rows; j++) {

    for (let i = 0; i < cols; i++) {

      curves[j][i].addPoint();

      curves[j][i].show();

​

    }

  }

      }

  // delete point

  else if(angle < 2* TWO_PI && angle > TWO_PI)

  {

    for (let j = 0; j < rows; j++) {

    for (let i = 0; i < cols; i++) {

      curves[j][i].removePoint();

      curves[j][i].show();

    }

  }

  }

  else

    {

          angle = 0;

    }

​

  angle += 0.02;

​

​

}