var prev;

​

function setup() {

  createCanvas(400, 400);

  background(240);

  pos = createVector(200, 200);

    prev = pos.copy();

}

​

function draw() {

  // background(220);

  stroke(0);

  strokeWeight(2);

  var step = p5.Vector.random2D();

  var r = random(100);

  if(r>95){

    step.mult(floor(random(30,50)));

  } else {

    step.mult(floor(random(1,5)));

  }

  pos.add(step);

  line(pos.x, pos.y, prev.x, prev.y);

  prev.set(pos);

}