Hmm... I&#x27;ve only ever heard about the reward checks for finding errors in the books. <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Knuth_reward_check" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Knuth_reward_check</a>