This was the title of a talk given by Erik Demaine at MIT two days ago, at Frank Geahry's Stata center, itself an example of art and puzzle. It was a lovely talk. Erik has done much of his work (starting at age 6!) with his dad, artist Martin Demaine. Martin was in the audience and even participated, and it was great to see the warm relationship between them. The theme of the talk was the way mathematics and art can inspire one another. The mathematics was broadly sketched, which enabled the talk to be much more accessible and personal than the typical math presentation. Erik's has an deep interest in origami, and he had many neat examples to show, including large pleated pieces. He concluded the talk (show?) with a number of magic tricks some of which were very funny and included members of the audience. In one trick he described a method of hanging a picture using two nails in a way that the picture would fall if either nail was removed. The mathematics involved was fairly simple, involving the commutator of a group. In his demonstration he had a volunteer hold out two arms to simulate the nails, and draped a large rope around his arms. It was quite effective, especially when he brought up a second volunteer to demonstrate that the method could be extended to any number of nails (4, in this case). All in all, this was an incredibly enjoyable presentation.