function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(50,20,10,10);

  angleMode(DEGREES);

   drawLine(width/2,width/2,5,14,n);

   n+=0.01;

}

​

function drawLine(tx,ty,angle,length,n){

  var shade=map(angle,5,560,50,200);

  stroke(shade,100);

  translate(tx,ty);  //rotation center

  rotate(angle);                 //clockwise

  line(0,0,length,0);   //relative to the rotation center  

  if(angle<560){

  drawLine(10,10,angle+n,length+0.5,n);

  }

}