let angle = 0;

function setup() {

  createCanvas(700, 400);

}

​

function draw() {

  background(220);

  strokeWeight(1);

  fill(0);

  // angleMode(DEGREES);

  stroke(255, 0, 0);

  line(width/2, height/2, width/2 + r*cos(angle), height/2 + r*sin(angle));

  line(width/2, height/2, width/2 + r*cos(-PI/5), height/2 + r*sin(-PI/5));

  stroke(0);

  ellipse(width/2, height/2, 10, 10);

  noFill();

  ellipse(width/2, height/2, r*2, r*2);

  fill(255, 255, 0);

  noFill();

  strokeWeight(3);

  stroke(255, 255, 0);

  arc(width/2, height/2, r*2, r*2, -PI/5, 0);

​

  fill(0);

  stroke(0);

  strokeWeight(1);

  ellipse(width/2+r*cos(-PI/5), height/2+r*sin(-PI/5), 5, 5);

  line(width/2+r*cos(-PI/5), height/2+r*sin(angle), width/2+r*cos(-PI/5), height/2+r*sin(-PI/5));

  textSize(15);

  // text("  (x, y) = (r*cos(θ), r*sin(θ))", width/2+r*cos(-PI/5), height/2+r*sin(-PI/5));

  // ellipse(width/2 + r*cos(angle), height/2 + r*sin(angle), 20, 20);

  // angle+=1;

}