According to Patterson's book the centipede-like drawing may represent exactly that. To it's left is a tall nearly straight line that probably means corn. A closer look at the latter shows it even has some leaves on the stalk. The intertwined lines immediately to the right of the corn may "signify the root of the squash vine, the criss-crossing water gourd vine, the bean plant, or the double gourd" if I interpret Patterson correctly. On the rock below these, the vertical line with three cross arms may represent "birthing."