var scalar = 300;  // set the radius of circle

var startX = 0; // set the x-coordinate for the circle center

var startY = 400;   // set the y-coordinate for the circle center

var x = 0;

​

function setup() {

  createCanvas(400, 400);

    background(255);

  angleMode(DEGREES);   // change the angle mode from radians to degrees

}

​

function draw() {

  // var x = startX + scalar * cos(angle);

  var y = startY - scalar * abs(sin(angle)); // make sin() always positive with abs()

  ellipse(x, y, 8);

  angle++;  // increment angle for the next frame

  x += 0.5; // increment the x-coordiate for the next frame

    if(angle%180 == 0) {

    scalar *= 0.7;  // slowly decrease the value of scalar after each bounce

  }

}