body {
  font-family: Arial, sans-serif;
  text-align: center;
}
#container {
  position: relative;
  width: 800px;
  height: 500px;
  margin: 0 auto;
  border: 1px solid #333;
  overflow: hidden;
  background-color: #f0f0f0;
}
.ball {
  position: absolute;
  width: 20px;
  height: 20px;
  background-color: red;
  border-radius: 50%;
  will-change: transform; /* Hint to the browser for optimization */
}
#optimizeBtn {
  margin: 20px;
  padding: 10px 20px;
}