“Round, round baby round, round / Spinning out on me”. It’s not explicit whether the underlying theme of this Sugababes song is an appreciation of mechanical timekeeping – the repetition of the lyric “got my kicks for free” casts doubt on the idea – but Mses Buchanan, Buena and Range were bang on the money if so. Watches (and clocks; and sundials, for that matter) are notable for their circular nature. Circular springs unwind to power an array of wheels, turning hands through 360 degrees to tell you that you’re late for another meeting. In a perfectly standard example of form following function, watches tend to come in round cases, too.