Previously in this series: The “lost boarding pass” puzzle The “deadly board game” puzzle The “knight on an infinite chessboard” puzzle The “largest stock profit or loss” puzzle The “birthday paradox” puzzle I have an interest in probability puzzles and riddles, and especially in simulating them in R. I recently learned about Feller’s coin-tossing puzzle, from the book Mathematical Constants by Steven Finch. (I recommend the book if you like the topic too!) Mathematician William Feller posed t...