A "supertask" is something that seems impossible at first, like climbing a very tall mountain or writing a novel. It takes a lot of planning and hard work, but it can be done if you break the task down into smaller, more manageable chunks. For example, if you wanted to climb a tall mountain, you would first need to get in shape, then figure out the route, buy the right gear, and find a group of people to help you. Once you have done all these things, you can slowly work your way up the mountain until you eventually reach the summit.