circles in the square

let speed = 1000;
let d = 300,
  n = 0,
  total = 0;

function setup() {
  createCanvas(600, 600);
  rectMode(CENTER);
  background(245, 255, 255);
}

function draw() {
  noFill();
  strokeWeight(0.5);
  translate(width / 2, height / 2);
  rect(0, 0, d, d);
  stroke(255, 255, 255, 2);
  for (let i = 0; i < speed; i++) {
    x1 = random(-d / 2, d / 2);
    x2 = random(-d / 2, d / 2);
    y1 = random(-d / 2, d / 2);
    y2 = random(-d / 2, d / 2);
    r = dist(x1, y1, x2, y2) / 2;
    cx = x1 + (x2 - x1) / 2;
    cy = y1 + (y2 - y1) / 2;
    stroke(random(100, 255), random(150, 255), random(150, 255), 10);
    circle(cx, cy, r * 2);
    if (
      cx + r > d / 2 ||
      cx - r < -d / 2 ||
      cy + r > d / 2 ||
      cy - r < -d / 2
    ) {
      n++;
    }
    total++;
  }
  stroke(255, 255, 255, 5);
  fill(235, 255, 255, 5);
  rect(0, 0, d, d);
  push();
  fill(235, 255, 255);
  if (mouseIsPressed) {
    rect(-width / 2 + 20, -height / 2 + 20, 280, 140);
    fill(0);
    stroke(0);
    text("total: " + total, -width / 2 + 20, -height / 2 + 20);
    text("n: " + n, -width / 2 + 20, -height / 2 + 40);
    p = round(n / total, 10);
    text("p: " + p, -width / 2 + 20, -height / 2 + 60);
    text("1 - π/6 ~ 0.476401224402", -width / 2 + 20, -height / 2 + 80);
    pop();
  }
}