An aegishjalmar can take on many different specific forms but in general they are all composed of the same small buildings blocks of ancient Norse runes. They begin with a simple cross in the middle and grow from there. Frequently they are used as talismans or protective devices. However, it is functionally impossible to tell the meaning of any particular one, since the small runes that make them up serve general functions — such as collecting energy or routing it from one place to another. Only the person who created the aegishjalmar, giving it a certain purpose upon creation, can ever truly say what it means.