1612turtlestack

// a simple version of Papert's turtle

var x = [];

var y = [];

var a = [];

var d = 10;

var t = 30; // turn amount

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  init();

  strokeWeight(10);

  noLoop();

}

​

function draw() {

}

​

function keyTyped() {

  if(key=='c') init();

  if(key=='F') // draw forward

  {

    let x1 = x[x.length-1] + d*cos(a[a.length-1]);

    let y1 = y[y.length-1] + d*sin(a[a.length-1]);

    line(x[x.length-1], y[y.length-1], x1, y1);

    x[x.length-1] = x1;

    y[y.length-1] = y1;

    redraw();

  }

  if(key=='+') // turn right

  {

    a[a.length-1]+=radians(t);

  }

  if(key=='-') // turn left

  {

    a[a.length-1]-=radians(t);

  }

  if(key=='[') // start branch

  {

    x.push(x[x.length-1]);

    y.push(y[y.length-1]);

    a.push(a[a.length-1]);

  }

  if(key==']') // end branch

  {

    x.pop();

    y.pop();

    a.pop();

  }

}

​

function init() {

  background(255);

  x = [];

  y = [];

  a = [];

  x[0] = width/2;

  y[0] = height/2;

  a[0] = PI*3/2;

}

​

​