let x;

let y;

​

// Declare a variable for the horizontal speed of the ball

let xspeed = 1;

//ySpeed

let yspeed = 2;

​

function setup() {

  createCanvas(400, 400);

  // Initialize the position in the center

  x = width / 2;

  y = height / 2;

}

​

function draw() {

  background(220);

  drawellipse();

  //move

  speed();

  // control the bounce 

  direction();

}

// Move the ball ball, either right or left

//   x += xspeed;

//   y += yspeed;

​

// Simplified Version:

// When the ball is at either left or right border

//   if (x <= 0 || x >= width) {

//     // Flip the sign of the direction

//     xspeed *= -1;

//   }

//   if (y <= 0 || y >= height) {

//     yspeed *= -1;

//   }

​

function drawellipse() {

  // Draw the ball

  ellipse(x, y, 50, 50);

}

​

function speed() {

  x += xspeed;

  y += yspeed;

}

​

function direction() {

  if (x <= 0 || x >= width) {

    // Flip the sign of the direction

    xspeed *= -1;

  }

  if (y <= 0 || y >= height) {

    yspeed *= -1;

  }

}

​