let angle = 30;

let increment = 1;

function setup() {

  createCanvas(400, 400);

  r = width/4;

  angleMode(DEGREES)

}

​

function draw() {

  background(255);

  translate(width/2,height/2)

  scale(1, -1);

  fill(150)

  circle(0,0,r*2)

  line(0,0,cos(angle)*r,sin(angle)*r)

  push()

  translate(cos(angle)*r,sin(angle)*r)

  line(0,0,cos(90-angle)*width,-sin(90-angle)*width)

  line(0,0,-cos(90-angle)*width,sin(90-angle)*width)

  pop()

  angle += 1;

}

​