createCanvas(300, 300);

  let foo = 50; // create and initialize a variable

​

  while (foo < width) { // keep going as long as the condition is true

    ellipse(50, foo, 40, 40);

    ellipse(100, foo, 40, 40);

    ellipse(200, foo, 40, 40);

    ellipse(150, foo, 40, 40);

    ellipse(250, foo, 40, 40);

        // modify the variable so something different happens next time

    foo = foo + 50; 

  }

}