Calvary cross
When all four arms are of equal length it is a Greek Cross, the cross in most frequent use among Eastern Christians. "The Latin cross suggests the actual form, while the Greek cross is idealized, the Greeks being essentially an artistic and poetic race." "The Greek cross is a symbol of the spread of the Gospel and of its triumphs in the four quarters of the world. It is the usual form wherever it is intended to express victory or is used as an ornament."
Greek cross
Another interesting form of the cross is the Tau-cross, so called because shaped like the Greek letter tau (T). The figure found in the tau-cross was the symbol of eternal life with the ancient Egyptians. The early Christians of Egypt adopted it and at first used it instead of other forms of the cross. It is yet seen in the early Christian sepulchers of that country. "It has been urged, with at least great probability, that this symbol of life was the form made by the children of Israel in blood upon their door-posts when the angel of death passed through the land of Egypt to smite the first-born, and it was perhaps the form of the cross on which the brazen serpent in the wilderness was lifted up."
Tau-cross
It is known, from these associations, as the cross of the Old Testament and as the "anticipatory cross"; also as the "cross of St. Anthony," the great hermit of Egypt and the father of monasticism.