Valknut

The valknut is a symbol consisting of three interlocked triangles, and appears on various Germanic objects. A number of theories have been proposed for its significance. The name valknut is an unattested modern invention used to describe the symbol, and was not used contemporarily when the symbol was used. The valknut has been compared to the three-horned symbol found on the 9th century Snoldelev Stone, and may be related to it. In Scandinavia today the term valknute is used for a square with a loop on each of its four corners. In the English language this symbol is called Saint John's Arms.
Due to the Norwegian name for the symbol, valknuter, and the fact that the symbol appears on picture stones with Odin and on burial gifts in the Oseberg ship burial, Rudolf Simek states that the symbol may have been associated with religious practices surrounding death.