Could you please explain what a 4x4 Pandiagonal magic square is? I'm curious to know how it differs from other types of magic squares and what makes it unique. Specifically, I'm interested in understanding the properties of this square and how the numbers are arranged to create a pandiagonal pattern. Additionally, I'd like to know if there are any specific rules or constraints that must be followed when creating a 4x4 Pandiagonal magic square.