There are stretches of bad road so intense they take your full concentration to navigate. You need to keep your vision focused at a permanent 10 meters in front of you, like a rattlesnake locking on to its prey, entranced by the heat signature. Your brain adjusts to this viewpoint, the constant blur of dirt and rock flowing under you. When you finally look up at the unmoving horizon, an optical illusion is created. It looks as if the background is shrinking, forever receding in front of your eyes. The goals of our expedition behave uncannily like this illusion.