let r = 160;

let tr = 180;

let tr2 = 210;

let arr = ["0", "π/6", "π/3", "π/2", "2π/3", "5π/6", "π", "7π/6", "4π/3", "3π/2", "5π/3", "11π/6"]

function setup() {

  createCanvas(600, 600);

}

​

function draw() {

  background(220);

  translate(width/2, height/2);

​

  noFill();

  ellipse(0, 0, 100, 100);

  ellipse(0, 0, 200, 200);

  ellipse(0, 0, 300, 300);

  textSize(15);

  textAlign(CENTER);

  fill(0);

  for (let i=0; i<count; i++){

    angleMode(DEGREES);

    line(0, 0, r*cos(i*360/count), r*sin(i*360/count));

    fill(0);

    text(i*360/count, tr*cos(360-(i*360/count)), tr*sin(360-(i*360/count))); 

    fill(255, 0, 0);

    text(arr[i], tr2*cos(360-(i*360/count)), tr2*sin(360-(i*360/count)));

  }

}