This black Saint Laurent sequin maxi dress features a round neck, a back keyhole and concealed zip fastening, long sleeves, an elasticated waist and all-over sequin embellishment. Back in 1480, Leonardo Da Vinci whipped together a sketch for a machine that, using levers and pulleys, would punch small disks out of a metal sheet. But it was never made. It looks like Saint Laurent beat Da Vinci to it. If this sequin dress is anything to go by.