In 1999 Christopher Monckton launched a new type of puzzle, similar to a jigsaw but with 209 plain green plastic pieces with geometric shapes. To attract interest, and increase sales, he offered a £1,000,000 prize for the first solution if found within a time limit of a few years. Professor Oliver Riordan here describes some of the ideas Alex Selby and he developed to work on this puzzle, and explains (without details!) how mathematicians think about such things. He also outlines where the inventor, who expected the puzzle to be much too hard to be solved, went wrong.
Professor Oliver Riordan is Professor of Discrete Mathematics and Tutor in Mathematics at St Edmund Hall, University of Oxford.
This is one of a series of Teddy Talks recorded at St Edmund Hall's Research Expo in 2015. Teddy Talks are short presentations (usually around 12 minutes long) by St Edmund Hall academics and postgraduate students about an aspect of their research, aimed at a non-specialist audience.