Morning on the Mars base, and the water tanks are running low. Blocks of ice have been dug out of the permafrost and left all over the cargo yard, and a fleet of small delivery rovers is waiting to haul them in. The trouble is that the rovers only know one trick: follow whoever is in front. So pixel Elon pulls on his boots, walks to the head of the line and starts the day's Rover Convoy.
Every block of ice he reaches adds another rover to the back of the train, and the convoy rolls a little faster with each load. The yard is ringed by walls of stacked regolith bricks, so one careless turn ends the run, and so does steering into the rovers you are leading. Now and then the greenhouse sends out its very first sprout, worth a big bonus if you get there in time. How long can the convoy grow before the tanks are full?
