“…Barning [9], and later independently several others [7,11,12,15,16,18,21] (see also [20]), showed: In some of the papers where this was discussed, the theorem has been described as placing the PPTs (a, b, c) with a odd and b even on the nodes of an infinite rooted ternary tree, with the root representing the "basic" triple (3,4,5), and where each triple (a, b, c) has three children, representing the multiplication of the triple (considered as a column vector) by the three matrices M 1 , M 2 , M 3 . In this paper, we consider a slightly different outlook.…”