let r = 10;

let old_mx = -1;

let old_my = -1;

​

function setup() {

  createCanvas(800, 400);

  background(0);

  for (let ni = 0;ni< 1000; ni++){

    let r_s = random()*5;

    noStroke();

    fill(255,200);

    ellipse(random()*width,random()*height,r_s,r_s);

  }

}

​

function draw() {

  if (mouseIsPressed) {

    let mx = mouseX;

    let my = mouseY;

    if (old_mx >= 0 && old_my >= 0) {

      for (let ni = 0; ni < n; ni++) {

        noStroke();

        strokeWeight(2);

        stroke(255, 226, 0);

        line(old_mx + r*cos(TWO_PI*ni/n), old_my + r*sin(TWO_PI*ni/n), mx + r*cos(TWO_PI*ni/n), my + r*sin(TWO_PI*ni/n));

      }

    }

    old_mx = mx;

    old_my = my;

  } else {

    old_mx = -1;

    old_my = -1;

  }

}