code: function getPixel(index) {
    validateIndex(index);
  
    var pixel = pixels[index].slice();
    pixel[3] = parseFloat((pixel[3] / 31).toPrecision(3));
  
    return pixel;
  }
docs: Gets the RGB and brightness values of the pixel at the <code>index</code>
  provided.
  
  @param {number} index - the horizontal position of the pixel (between 0 and 7 - inclusive)
  @return {number[]} An array containing the pixel information (red, green, blue, brightness).
  @throws {RangeError} If <code>index</code> is less than 0 or greater than 7.
  @throws {TypeError} If <code>index</code> is <code>null</code> or not a number.
  @public