We can also see by observing nature's forms -- the form of a tree, of a plant, of a flower, the forms of the animals and birds, and in the end the most developed and finished form of the human being -- that they all present a cross. One cross may be seen by observing the formation of man's head, the other cross can be seen by the whole form of mankind: it is ever a horizontal and a perpendicular line which suggest the symbol of the cross. There is no form that does not have a horizontal and a perpendicular line, and it is these two different aspects or directions which form the cross. In this way one can understand that in the mystery of form the cross is hidden.