var max_times = 10;

var SIZE = 400;



function setup() {

  createCanvas(SIZE, SIZE);

  noStroke();

  frameRate(2);

}



var times = 0;

var change = 1;



function draw() {

  background(10, 25, 300);



  fill(255, 255, 255);

  triangle(SIZE/3, 0, 0, SIZE, SIZE, SIZE);



  fill(255,25,0);

  SierpinskiGasket(SIZE/3, 0, 0, SIZE, SIZE, SIZE, times);



  times += change;



  if (times > max_times || times < 1) {

    change *= -1;

  }

}



function SierpinskiGasket(Ax, Ay, Bx, By, Cx, Cy, times) {

  if(times > 0) {

    SierpinskiGasket(Ax, Ay, (Ax + Bx) * 0.5, (Ay + By) * 0.5, (Ax + Cx) * 0.5, (Ay + Cy) * 0.5, times - 1);

    SierpinskiGasket(Bx, By, (Ax + Bx) * 0.5, (Ay + By) * 0.5, (Bx + Cx) * 0.5, (By + Cy) * 0.5, times - 1);

    SierpinskiGasket(Cx, Cy, (Bx + Cx) * 0.5, (By + Cy) * 0.5, (Ax + Cx) * 0.5, (Ay + Cy) * 0.5, times - 1);

  }

  triangle((Ax + Bx) * 0.5, (Ay + By) * 0.5, (Bx + Cx) * 0.5, (By + Cy) * 0.5, (Cx + Ax) * 0.5, (Cy + Ay) * 0.5);

}