Tarzan, the ape-man of the jungle, performed all his feats of strength and bravery by clinging to an intricate system of vines. He swung from the west side to the upper east side of the jungle at will. No lights. No traffic jams. Saving damsels in distress, foiling poachers, saving animals, catching bad guys. All his good works (his purpose in life) made possible because Tarzan knew the importance of clinging to the vine.