It starts as soon as I arrive. In Den Haag Centraal railway station, the kiosks, windows, lift shaft, piano and even the hoarding on the building site outside, are all cheerfully decked out in red, blue and yellow rectangles, black lines and an occasional patch of straight-sided white. Holland’s capital has gone Mondrian mad; the style of De Stijl (the modernist art movement to whichF he belonged) is plastered all over town, indeed over much of the country.