Most torpedo levels are crafted from wood or plastic - I have a fluorescent orange plastic one in my toolbox - but this one is an odd variant on the classic carpenter's conscience. Crafted from a forged block of aluminum, a steel plate, a pair of screws and a oil-filled capsule, it seems stolen from a prop house on the set of a machine-age science fiction melodrama. Though apparently quite old - research on its label has proved fruitless - it hints at the future that never came true, when utopian cities of curved, computer-designed crystal might have made something like it completely obsolete.