Details 457 came from Holbein's The Ambassadors, with its famous stretched-out image of a skull. It's called an "anamorphic projection". The skull only looks right when viewed from a very sideways angle - which was how it was shown in our Detail (to make it more tricky). Many have been fascinated by this enigmatic device, including the psychoanalytic theorist Jacques Lacan, who wondered: "How is it that nobody has ever thought of connecting this with the effect of an erection? Imagine a tattoo made on the sexual organ in a state of repose, and assuming its - if I may say so - developed form in another state." The picture is in the National Gallery, London.
The first three correct entries came from: L Dawson, London E9; H Smith, Croydon; I Patterson, Edinburgh
In which painting by which painter can you find this struggle?
Answers, on a postcard, to arrive by Friday 19 November, to: DETAILS 459, IoS, 1 Canada Square, Canary Wharf, London E14 5DL. Three winners will each receive a bottle of champagne