That was also my first impression but soon Tim and I decided that, even most of the drawings are very abstract and ambiguous, they seem painted or something of the like. Plough would scarify the stones, not paint over them.

If you browse back, you can notice that she has already consulted with some prehistorian, who dismissed her saying they were plough marks, with an agronomist who declared they could not be plough marks and that she has made a home chemical experiment that revealed that the pigment has iron (something that looked quite apparent to me on first sight).

I think that some resemble the Iberian rock art style, while others could be Tartessian or Iberian script characters (in one case I think the expression BABAAL can be read, though it depends what script interpretation you follow). Nevertheless many are too loose, abstract or merely imprecise to say what did the author wanted to express.