Definitely not surprised that the author is John Conway (and his coauthor). I took his course on Linear Algebra back in the day -- the man is a veritable real life troll (in a good way)
That's typical for mathematicians - even more so with extroverted ones. They approach rules as a game one can use at will as long as the rules remain true. Thus, playing pranks with rules can become enjoyable. Coincidentally, surprise is the quintessence of humour, some say.
The original meaning of the word "hacker" is related to this thinking. However, the focus is different. The hackers tend to achieve their goal in whatever "hacky" way possible while mathematicians see the rules itself as the game.
