var k = 4;
   var j = 5/8;

function setup() {
  createCanvas(500, 500);

}

function draw() {

  translate(width/2, height/2);
  beginShape();
  stroke('black');
  strokeWeight(3);

  for (var a = 0; a < TWO_PI * 7
      ; a += 0.02){
    //use k or j
    var r = 200 * cos(6/7 * a); 
    var x = r * cos(a);
    var y = r * sin(a);
    vertex(x, y);
  }
  endShape(CLOSE);
}