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/// <summary>
/// Gets the value in a single dimensional array that represents a three dimensional sequence.
/// </summary>
/// <typeparam name="T">The type of the array.</typeparam>
/// <param name="array">The array whose value is to be retrieves.</param>
/// <param name="width">The width of the three dimensional sequence.</param>
/// <param name="height">The height of the three dimensional sequence.</param>
/// <param name="x">The x index (0 to width - 1).</param>
/// <param name="y">The y index (0 to height - 1).</param>
/// <param name="z">The z index (0 to depth - 1).</param>
/// <returns>Returns the value stored in the array.</returns>
/// <exception cref="ArgumentOutOfRangeException">
/// width or height is less then 1.
/// </exception>
/// <remarks>
/// <p>This method provides an alternative to working with three dimensional arrays "var value = new int[3,3,3];" by operating 
/// on a single dimensional array using a math formula to determine the index into the array.</p>
/// <p>Think of a multi-layered image. Each image layer consists of a grid of cells defined by width * height.</p>
/// <p>We can use the formula "layer * (width * height)" to get the starting index of the layer in the array. 
/// To get the index in the image we can use the formula "(y * width) + x". 
/// Combining these two formulas we can access any grid cell of any layer in the array like so "(layer * (width * height)) + ((y * width) + x)".</p>
/// <p>This method does not perform range checking and will throw index out of range exceptions if invalid arguments are specified.</p></remarks>
public static T Get3D<T>(this T[] array, int width, int height, int x, int y, int z)
{
    if (width < 1)
    {
        throw new ArgumentOutOfRangeException("width");
    }

    if (height < 1)
    {
        throw new ArgumentOutOfRangeException("height");
    }

    return array[(z * (width * height)) + ((y * width) + x)];
}