Besides these symbolical meanings the cross is a natural sign that man has always made either from his artistic faculty or from his reasoning faculty. It is the nature of light to spread its rays, especially when the light is in its perfection. By looking at the sun - at the setting sun in particular - one finds lines forming on the sky and on the earth: first there is one straight line, and if one watches carefully out of that first vertical line a horizontal line develops. By keen observation of light one realizes that it is the nature of light to form a perpendicular and a horizontal line; and if it is the nature of the external light to form a cross it is also the nature of the inner light. The external light is the reflection of the inner light, and it is the nature of the inner light that is expressed in the outer light; by this one can see that the inner light is not only manifested in the outer light, but that the outer light is the picture of the inner light.