// put setup code here

  createCanvas(600, 600);

}

let xy = [];

let newxy = Array(100);

let flat = false;

​

function draw() {

  // put drawing code here

  background("rgba(0,142,174,1)");

  stroke("#ADEFD1FF");

  noFill();

  strokeWeight(4);

  beginShape();

  for (var i = 0; i < xy.length; i++) {

    vertex(xy[i][0], xy[i][1]);

  }

  endShape();

  if(flat){

    flatten();

  }

}

​

function flatten(){

  for (var i=1; i<xy.length-1;i++){

    xy[i][0] = (xy[i-1][0] + xy[i+1][0])/2;

    xy[i][1] = (xy[i-1][1] + xy[i+1][1])/2;

  }

}

​

function mouseDragged(){

  flat=false;

  if (xy.length < 100) {

      xy.push([mouseX, mouseY]);

    } else {

      xy.shift();

    }

}

​

function mouseReleased(){

  flat = true;

}