​

const stepsize = 25;

let currentstepsize = stepsize;

let anglerange;

let showthing=true;

​

function setup() {

  createCanvas(600, 600);

  //generate path here all at once

  path = [[0,height/2]] //sample code

  anglerange  = 0.5*PI;;

}

​

function draw() {

  background(255);

  if(showthing){

    text('hold left mouse button to draw', width/2, height/2)

    if(mouseIsPressed){

      showthing=false;

    }

  }

  if(pmouseX!=mouseX||pmouseY!=mouseY){

    currentstepsize=stepsize;

  }

  if(mouseIsPressed){

    if(pmouseX==mouseX && pmouseY==mouseY){

      currentstepsize = 1.01 * currentstepsize;

    }

    let direction = atan((mouseY-path[path.length-1][1])/(mouseX-path[path.length-1][0])) + (PI/2)*Math.sign(mouseX-path[path.length-1][0]) - PI/2;

    direction += (random(anglerange) - anglerange/2);

    let step = random(currentstepsize/2,currentstepsize);

    path.push([path[path.length-1][0] + cos(direction)*step, path[path.length-1][1] + sin(direction)*step]);

  }

  drawPath(); //draws the path

}

​

function drawPath(){

  stroke(0);

  for(let i=1;i<path.length;i++){

    line(path[i-1][0],path[i-1][1],path[i][0],path[i][1]);

  }

}