For a really a hard task, you have to do a task, e.g. create a solar system.
But, you have to do 100 observations of what happened. Of course, no DEILDs. For create a solar system, you would have to revisit it 100 times, and write a detailed description for each lucid. Some have said this task might get unenjoyable, but wouldn't it be fun and engaging to create a solar system from scratch, checkout the planets, map them, discover creatures, watch them evolve, meet new civilizations, and make new friends. Then, you can move on to another star!
https://www-tc.pbs.org/wgbh/nova/ass...ystem-merl.jpg