«The Dinosaur Who Built a Wall» by Tonko Stuurman

A story for 7–9 year olds set in the great age of the dinosaurs of a young plant-eating dinosaur who dared to think! His name is DVJ. Some alien people landed on earth and gave lessons to the dinosaurs on how to think, but mostly failed and then they flew off. DVJ is tired of running away from the meat-eaters 'T'Rex' and his hostile partner 'Trexie', not to mention Gigantosaurus the biggest and meanest of them all. DVJ plays in the goo beside a lake and soon learns how to make mud bricks, inspired by the thinking lessons of the aliens. He builds a wall which he calls a 'dino-cliff' and hides behind it when the hungry meat-eaters come by. Along the way, he manages to make mud balls and uses them to scare the meat-eaters off, by aiming at them from behind the wall. In doing so, he becomes the champion of the plant-eaters.