2013-06-05
Explanation
This comic is a joke about floating-point arithmetic errors in computer science. In the first panel, a robot sits at a computer. In the second panel, we see a flashback labeled "Earlier..." showing the robot accessing "The Secret Robot Internet." To prove it is not human (a reverse CAPTCHA), the robot must answer "0.1 + 0.2 = ?" and it enters "0.30000000000000004" -- which is the famously incorrect result that computers produce due to the way floating-point numbers are stored in binary.
The joke plays on the concept of CAPTCHAs, which are tests designed to prove a user is human. Here, the robot internet has an anti-human CAPTCHA that only a computer would get "right" -- because a human would simply answer "0.3," while a computer using IEEE 754 floating-point arithmetic would produce the slightly off result. This is a well-known quirk in programming: in most languages, 0.1 + 0.2 does not exactly equal 0.3 due to binary representation limitations.
The votey (bonus panel) shows a handwritten note listing two equivalent options: "Option 1: Read Reddit" and "Option 2: Directly remove 6 hours/day from lifespan." This is an unrelated gag about the addictive, time-wasting nature of Reddit, suggesting that spending hours on the site is essentially the same as losing that time from your life.