Author Archives: Simon Singh

“Lisa the Simpson” puzzle

Fans of Richard Wiseman’s Friday puzzle will have noticed a particularly lovely one last week. Why is this correct?

As Richard explained, you simply have to mirror the left hand digit and move it over to the right hand digit in order to create a shape like a fish, a figure eight or a triangle.

This reminded me of a puzzle from an episode of The Simpsons titled “Lisa the Simpson”. When I met David X. Cohen, part of the writing team for that episode, he told me that he had suggested the puzzle and showed me his original sketches.

5.4 Lisa puzzle script 1

The puzzle, almost as it appeared in the episode, is the third line on this page of doodles. Solving the problem relies on noticing that the left and right halves of each symbol are mirror images of each other. The right half of the first symbol is 1, and the left half is its reflection. The right half of the second symbol is 2, and the left half is its reflection. The pattern continues with 3, 4, and 5, so the sixth symbol would be 6 joined to its own reflection.

The upper line suggests Cohen was thinking of using the sequence (3, 6, 9), but this idea was abandoned, probably because the fourth element, 12, would have required two digits.

The second and fourth lines, which show the sequences (1, 4, 2, 7) and (1, 4, 2), were also abandoned. I cannot identify the patterns behind these two sequences, and Cohen can no longer remember what he had in mind. Maybe you have some ideas.

Ps. If you want to be reminded of Richard Wiseman’s Friday puzzle each week, then follow him on twitter @RichardWiseman. And you can find his daily blog at

PPs. And if you have not caught any of Richard’s brilliant “Bets” youtube videos, then they are really worth watching. The latest video has just been released.


Kirkus review: “A fun trip with the ultimate TV vehicle for pop culture mathematics.”

The influential US-based journal Kirkus has given the book a great review. If you are a subscriber, then you will find it here. If not, then you will have to wait until October 18, 2013, when the link will be open to everyone. For the time being, I can quote the reviews headline: “A fun trip with the ultimate TV vehicle for pop culture mathematics.”

Kirkus Book Reviews

Extract from the book serialised in the Observer

The book is not yet published (October 10), so this is the first time anyone will have read anything from ‘The Simpsons and Their Mathematical Secrets’. The response has been great, both in terms of twitter and the comments after the article. Shockingly, this turned out to be most read article on the entire Guardian/Observer website on Sunday.

The Simpsons’ secret formula: it’s written by maths geeks

When one of Britain’s best-known science writers went to Los Angeles to meet the show’s writers for a new book, he found a team dedicated to inserting gags about complex maths problems. And you thought it was just a cartoon… read more.