Perhaps somebody can research into the origins of the Greek cross. The Greek cross was prominent in Byzantine and therefore Orthodox art. The Greek cross has four equal sides unlike the more popular Latin cross (the common Christian cross symbol as most of us know it), which was actually a later development.

I have wondered about it, since the angles of the Greek cross correspond the four cardinal/compass points, which in latter-day knowledge has much symbolism.

In the Greek Orthodox section of the Church of the Holy Sepulchre in Jerusalem, there is also the so-called omphalos, or Navel of the World stone. It is said that this stone marks the navel or very center of the world, hence Jerusalem, where all compass points, in short, all exactness, direction and wholeness begin. And isn’t Jerusalem a symbol for Zion, the celestial city of God?

Lastly, the Greek cross adorned an ancient Eastern Orthodox priestly garment, the omophorion. It is a band of brocade originally made of wool and worn around the neck and shoulders. What is interesting is that early Byzantine icons depict saints wearing omophorions decorated with Greek crosses. The cross-adorned omophorion, in particular, was a distinguishing symbol of the early Christian priesthood.

The gamma symbol clearly has other temple connections throughout the world, as is also related on the wiki page for the swastika, as the swastika is a combination of four gamma symbols and is also referred to as a gammadion:

In particular, the left-facing swastika is often carved in a see-through lattice in entrance doors of Buddhist temples in China. When exiting the temple, one sees the reverse side of this lattice on the same door, which looks like a right-facing swastika.

Swastikas were found on pottery at the Gebel Barkal temples as well as in digs corresponding to the later X-Group peoples.

Throughout the subcontinent of India, it can be seen on the sides of temples, religious scriptures, gift items, and letterheads. The Hindu god Ganesh is often shown sitting on a lotus flower on a bed of swastikas.

The swastika is found all over Hindu temples, signs, altars, pictures and iconography where it is sacred. It is used in Hindu weddings, festivals, ceremonies, houses and doorways, clothing and jewelry, motor transport and even decorations on food items such as cakes and pastries.

Swastika on a Buddhist temple in Korea.

On maps in the Taipei subway system a swastika is employed to indicate a temple, next to a cross indicating a Christian church.

All Jain temples and holy books must contain the swastika and ceremonies typically begin and end with creating a swastika mark several times with rice around the altar. Jains use rice to make a swastika (also known as “Sathiyo” in the state of Gujarat, India) in front of idols in a temple.

It was the symbol of power (in attests picture of swastika on coins of Mieszko I). The power both lay and divine, because it was often placed on altars in pagan temples.

The swastika symbol is also known in these contexts by a number of names, especially gammadion.

The entire article on Wikipedia about the swastika symbol is very interesting, noting that it’s current controversial significance was because of its appropriation by Nazi Germany. But before that it was used extensively in the Western world also:

The swastika symbol was popular as a good luck or religious/spiritual symbol in the United States, prior to its association with Nazi Germany. The symbol remains visible on numerous historic buildings, including sites that are listed on the National Register of Historic Places. It also appeared on tiles, lampposts, metal valves, tools, surfboards, stock certificates, brand names, place names, medals, commercial tokens, postcards, souvenirs, rugs and clothing.

http://en.wikipedia.org/wiki/Cross
(scroll all the way down to “cross voided”)

Related, of course, is the swastika or “crux gammata” -

From the wiki page on swastika:
Seen as a cross, the four lines emanate from the center to the four cardinal directions.
The most common association is with the Sun. Other proposed correspondences are to the visible rotation of the night sky in the Northern Hemisphere around the pole star.