Here are some alternate explanations for the possible meaning of these lines cited from wikipedia:

Phyllis Pitluga, senior astronomer at the Adler Planetarium and a protégé of Reiche, performed computer-aided studies of star alignments. She asserted the giant spider figure is an anamorphic diagram of the constellation Orion. She further suggested that three of the straight lines leading to the figure were used to track the changing declinations of the three stars of Orion’s Belt. In a critique of her analysis, Dr. Anthony F. Aveni noted she did not account for the other 12 lines of the figure; he commented generally on her conclusions, saying:

I really had trouble finding good evidence to back up what she contended. Pitluga never laid out the criteria for selecting the lines she chose to measure, nor did she pay much attention to the archaeological data Clarkson and Silverman had unearthed. Her case did little justice to other information about the coastal cultures, save applying, with subtle contortions, Urton’s representations of constellations from the highlands. As historian Jacquetta Hawkes might ask: was she getting the pampa she desired?

What do you think?  If you have any theories or explanations feel free to comment.