// slightly below PI. I have the theory that there is a bias

// towards 45 and 135 degree angles because of the diagonals.

// Now I filter out all the initial, unscaled points that are

// not inside the circle around the center. I'm still not using

// PI in the source. The results now seem more reasonable.

​

// Somehow I have a feeling that Buffon's algorithm only works

// if you have a room big enough that no toothpick ever hits the

// wall. Maybe an idea for a future coding challenge? Use a physics

// engine to simulate toothpicks in a room with walls.

​

// I also added some other optimizations.

​

let t = 20;

let l = 15;

let speeed = 10000;

let crossesCount, total;

let pieP;

let syze = 400;

let radius;

​

function setup() {

    createCanvas(syze, syze);

    background(0);

    stroke(255);

    for (let x = 0; x <= width; x += t) {

      line(x, 0, x, height);

    }

    radius = syze / 2;

    radiusSquared = radius * radius;

    crossesCount = 0;

    total = 0;

    pieDiv = createDiv("0.0");

    pieDiv.style("background-color", "#000");

    pieDiv.style("color", "#FF0");

}

​

function circlePoint() {

    let x, y, dx, dy;

    do {

      x = random(syze);

      y = random(syze);

      dx = x - radius;

      dy = y - radius;

    } while (dx * dx + dy * dy > radiusSquared);

    return [x, y];

}

​

function draw() {

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

      let x0, x1, y0, y1;

      [x0, y0] = circlePoint();

      [x1, y1] = circlePoint();

      xc = (x0 + x1) / 2;

      yc = (y0 + y1) / 2;

      let dst = dist(x0, y0, x1, y1);

      let scl = l / dst;

      let nx0 = xc + (x0 - xc) * scl;

      let ny0 = yc + (y0 - yc) * scl;

      let nx1 = xc + (x1 - xc) * scl;

      let ny1 = yc + (y1 - yc) * scl;

​

      let col0 = floor(nx0 / t);

      let col1 = floor(nx1 / t);

​

      if (col0 != col1) {

        ++crossesCount;

        stroke(0,255,0);

      } else {

        stroke(255,0,0);

      }

      line (nx0, ny0, nx1, ny1);

    }

    total += speeed;

    let prob = crossesCount / total;

    let pie = 2 * l / (prob * t);

    pieDiv.html(pie);

}

​