"Lug, the Celtic God of Light", Fig. 7-1,
Barry Fell,Bronze Age America, p. 155.
As can be clearly seen below the figure in the photograph there are a large number of linear markings of various ages (including a historic addition in English) superimposed, and it would not seem to be much trouble to find any rune or letter you wished by careful selection of the right lines. Indeed, in his figure 7-1, Fell’s last two letters can be seen in the close-up to consist of the disassembled neck and torso of a “V-Necked Anthropomorph” figure from a prehistoric petroglyph. The proper question here is not what was found by careful selection (and a lot of imagination) on the rock, but instead what was overlooked because it did not fit with preconceptions intent on finding that message.
"Lug, God of Light", Fig. 7-2, Barry Fell,
Bronze Age America, 1982, p.158.