Five Songs on the Heaven Principles

My fengshui book is nearing completion. Here is an extract.

....To understand how this comes about, we need to refer to the principle of the relationship of the heaven, earth and man principals. Before we get lost, these principals are not some complex philosophical ideals but simply the three divisions of the twenty four directions found on the luopan. (Refer to the notes on the 24 mountains of the luopan). In practice we would work towards aligning all doors to the same principal. For example if the main door is orientated with a heaven mountain, then all the other doors should be to heaven mountains. There is no such thing as another alternative orientation....