The cave was much longer than they had expected when they entered it. Now dry, the underground river that dug its way through the rock went up and down all the time. It occasionally carved huge halls, but they had to crawl every now and then. “Here we are,” said Tlön and stopped in his tracks as they entered a small hall with a high, round dome. He pointed at a bunch of parallel lines scratched into one of the walls. “This is quite recent,” said one of his mates after careful inspection. “One more planet…,” mumbled another mate. “Give them about ten-thousand rounds of their star,” said Tlön, “and we will be able to communicate with them.” They all nodded. “The only question is which way they will go,” he sighed and motioned them forward with his head. The end of the cave was some way off still, but now they inspected the walls with great care.