There is a joke in the same vein where scientists try and train fleas to learn and obey commands to jump. They find that the hardest fleas to teach how to jump

There is a joke in the same vein where scientists try and train fleas to learn and obey commands to jump. They find that the hardest fleas to teach how to jump on command are those with all legs removed: they’re the most stubborn and refuse to jump when asked 100% of the time.