Using a "periodic table of element" apporach, Bible books are laid out in order from left to right, and in some cases top to bottom. The Hebrew Scriptures are kept in the cool color range, and the Greek Scriptures are in warm color tones. Sections of books are also color coded by subject matter, for example, Poetic, Prophetic, Gospels, Letters, etc. Books  also maintain a basic size relationship to each other. The colors, sizes, and positions make it easy to remember a books location and relationships with surrounding books.