Cosy Day

Trompe l'oeil reached its height in 17th-Century Europe, in paintings so realistic that the objects in them seem to be projecting forward from the canvas into the viewer's space, close enough to touch. In a common motif, straps seem to be physically holding up various objects – such as sheet music or letters – on a display board, when the entire image, wooden frame included, is actually a painted illusion. The Cubists, of course, did the opposite, fracturing images to grasp an object's essence. In her memoir Life With Picasso, Francoise Gilot quotes the artist as saying, "We tried to get rid of trompe l'oeil to find a trompe l'esprit. We didn't any longer want to fool the eye; we wanted to fool the mind." But a major point of the exhibition is that mind games questioning the nature of reality and of art itself were already there in the most ambitious 17th-Century trompe l'oeil paintings. "Any mimesis is not real, despite how real it might look," Braun tells BBC Culture. Trompe l'oeil, she says, offered a "sophisticated and philosophical discourse in the Baroque period, and then again when the Americans took it up in the 1890s," a pattern the Cubists were heir to.

Ley lines? Energy lines? Surely the preserve of myth makers and fairy followers? Not to start with. The term was originally posited, just three years after the end of World War One, by Alfred Watkins, a councillor in rural Herefordshire in the UK. Born in 1855 into a well-to-do farming family, Watkins was also an amateur archaeologist; it was while out riding in 1921 that he looked out over the landscape and noticed what he later described as a grid of straight lines that stood out like "glowing wires all over the surface of the county", in which churches and standing stones, crossroads and burial mounds, moats and beacon hills, holy wells and old stone crosses, appeared to fall into perfect alignment.