Koch + Truchet - OpenProcessing

sketch
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// By Roni Kaufman
// https://ronikaufman.github.io/
​
function setup() {
  createCanvas(windowWidth, windowHeight);
  noLoop();
  noFill();
  strokeWeight(1);
  stroke(0, 220, 250);
}
​
function draw() {
  background(0, 20, 50);
  translate(width/2, height/2);
  
  let s = 250;
  let n = 3;
  let v1 = p5.Vector.fromAngle(5*PI/6, s);
  let v2 = p5.Vector.fromAngle(PI/6, s);
  let v3 = p5.Vector.fromAngle(-PI/2, s);
  
  divide(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, n+1);
  kochCurve(v1.x, v1.y, v3.x, v3.y, n);
  kochCurve(v3.x, v3.y, v2.x, v2.y, n);
  kochCurve(v2.x, v2.y, v1.x, v1.y, n);
}
​
function prop(x1, y1, x2, y2, k) {
  let x3 = (1-k)*x1 + k*x2;
  let y3 = (1-k)*y1 + k*y2;
  return [x3, y3];
}
​
function thirdPoint(x1, y1, x2, y2) {
  let x3 = (x2-x1)/2 + sqrt(3)*(y2-y1)/2 + x1;
  let y3 = -sqrt(3)*(x2-x1)/2 + (y2-y1)/2 + y1;
  return [x3, y3];
}
​
function kochCurve(x1, y1, x2, y2, n) {
  let [xA, yA] = prop(x1, y1, x2, y2, 1/3);
  let [xB, yB] = prop(x1, y1, x2, y2, 2/3);
  let [xC, yC] = thirdPoint(xA, yA, xB, yB);
  if (n > 0) {
    kochCurve(x1, y1, xA, yA, n-1);
    kochCurve(xA, yA, xC, yC, n-1);
    kochCurve(xC, yC, xB, yB, n-1);
    kochCurve(xB, yB, x2, y2, n-1);
    divide(xA, yA, xB, yB, xC, yC, n);
  } 
  if (n == 1) {
    /*
    let d = dist(xA, yA, xB, yB);
    arc(xC, yC, 2*d/3, 2*d/3, atan2(yA-yC, xA-xC), atan2(yB-yC, xB-xC));
    arc(xA, yA, 2*d/3, 2*d/3, atan2(y1-yA, x1-xA), atan2(yC-yA, xC-xA));
    arc(x2, y2, 2*d/3, 2*d/3, atan2(y1-yA, x1-xA), atan2(yC-yA, xC-xA));
    arc(xB, yB, 2*d/3, 2*d/3, atan2(yC-yB, xC-xB), atan2(y2-yB, x2-xB));
    arc(x1, y1, 2*d/3, 2*d/3, atan2(yC-yB, xC-xB), atan2(y2-yB, x2-xB));
    */
    line(x1, y1, xA, yA);
    line(xA, yA, xC, yC);
    line(xC, yC, xB, yB);
    line(xB, yB, x2, y2);
  }
}
​
function divide(x1, y1, x2, y2, x3, y3, n) {
  if (n > 1) {
    let [xA, yA] = prop(x1, y1, x2, y2, 1/3);
    let [xB, yB] = prop(x1, y1, x2, y2, 2/3);
    let [xC, yC] = prop(x2, y2, x3, y3, 1/3);
    let [xD, yD] = prop(x2, y2, x3, y3, 2/3);
    let [xE, yE] = prop(x3, y3, x1, y1, 1/3);
    let [xF, yF] = prop(x3, y3, x1, y1, 2/3);
    let [xG, yG] = prop(xF, yF, xC, yC, 1/2);
    divide(x1, y1, xA, yA, xF, yF, n-1);
    divide(xA, yA, xB, yB, xG, yG, n-1);
    divide(xB, yB, x2, y2, xC, yC, n-1);
    divide(xG, yG, xF, yF, xA, yA, n-1);
    divide(xC, yC, xG, yG, xB, yB, n-1);
    divide(xF, yF, xG, yG, xE, yE, n-1);
    divide(xG, yG, xC, yC, xD, yD, n-1);
    divide(xD, yD, xE, yE, xG, yG, n-1);
    divide(xE, yE, xD, yD, x3, y3, n-1);
  } else {
    drawTriangle(x1, y1, x2, y2, x3, y3);
  }
}
​
function drawTriangle(x1, y1, x2, y2, x3, y3) {
  /*
  fill(255, 0, 0);
  stroke(255, 0, 0);
  triangle(x1, y1, x2, y2, x3, y3);
  noFill();
  stroke(0, 20, 50);
  */
  let d = dist(x1, y1, x2, y2);
  let r = random(1);
  if (r < 1/3) {
    arc(x1, y1, 2*d/3, 2*d/3, atan2(y3-y1, x3-x1), atan2(y2-y1, x2-x1));
    arc(x2, y2, 2*d/3, 2*d/3, atan2(y1-y2, x1-x2), atan2(y3-y2, x3-x2));
    arc(x3, y3, 2*d/3, 2*d/3, atan2(y2-y3, x2-x3), atan2(y1-y3, x1-x3));
  } else if (r < 2/3) {
    arc(x1, y1, 4*d/3, 4*d/3, atan2(y3-y1, x3-x1), atan2(y2-y1, x2-x1));
    arc(x2, y2, 4*d/3, 4*d/3, atan2(y1-y2, x1-x2), atan2(y3-y2, x3-x2));
    arc(x3, y3, 4*d/3, 4*d/3, atan2(y2-y3, x2-x3), atan2(y1-y3, x1-x3));
  } else {
    let x12 = (x1+x2)/2;
    let y12 = (y1+y2)/2;
    arc(x12, y12, d/3, d/3, atan2(y1-y12, x1-x12), atan2(y2-y12, x2-x12));
    let x23 = (x2+x3)/2;
    let y23 = (y2+y3)/2;
    arc(x23, y23, d/3, d/3, atan2(y2-y23, x2-x23), atan2(y3-y23, x3-x23));
    let x31 = (x3+x1)/2;
    let y31 = (y3+y1)/2;
    arc(x31, y31, d/3, d/3, atan2(y3-y31, x3-x31), atan2(y1-y31, x1-x31));
  }
}