The Sign of the Pentagram
The pentagram represents the concept of "man made perfect"... incorporating the elemental universe within the body and soul of man, the macrocosm within to microcosm. The points on the pentagram are usually assigned as in the diagram below.
There is a complex system of invoking and banishing for each of the elements, which is of ceremonialist origin and which is used in some Wiccan groups. However, most Wiccans use the simplified version, as in the diagrams below.