Both Nick Clegg and Andrew Mitchell have said it's time to "draw a line" under the row over the chief whip's intemperate comments to a police officer. But why do politicians use this phrase so often?
Plot points with coordinates where \(x\) and \(y\) are equal. Three points are sufficient, but more can be plotted. Draw a line through the plotted points. If \(x\) is positive, \(y\) is negative. If ...